CN117285938A

CN117285938A - Liquid-crystalline medium

Info

Publication number: CN117285938A
Application number: CN202310739210.1A
Authority: CN
Inventors: 黄启舜; S·C·洛特; 李熙规; 杨明辉; H·赫施曼; 周光廷; S-C·洪; A·哈恩; P·武赫
Original assignee: Merck Patent GmbH
Current assignee: Merck Patent GmbH
Priority date: 2022-06-23
Filing date: 2023-06-21
Publication date: 2023-12-26
Also published as: JP2024002955A; EP4296334A1; US20240002728A1

Abstract

The present invention relates to a Liquid Crystal (LC) material with negative dielectric anisotropy as defined in claim 1 and its use for optical, electro-optical and electronic purposes, for example in LC displays, in particular energy-saving displays based on the ECB, IPS or FFS effect.

Description

Liquid-crystalline medium

Technical Field

The present invention relates to Liquid Crystal (LC) media with negative dielectric anisotropy and their use for optical, electro-optical and electronic purposes, in particular in LC displays.

Background

One type of Liquid Crystal Display (LCD) mode currently in use is the TN ("twisted nematic") mode. However, a disadvantage of TN LCDs is that the contrast ratio has a strong dependence on viewing angle.

In addition, so-called VA (vertical alignment) displays with a wider viewing angle are known. The LC cell of a VA display contains a layer of LC medium between two transparent electrodes, where the LC medium typically has a negative dielectric anisotropy. In the off-state, the molecules of the LC layer are aligned perpendicular to the electrode surface (homeotropically) or have an inclined homeotropic alignment. When a voltage is applied to both electrodes, a realignment of LC molecules parallel to the electrode surfaces occurs.

Also known are so-called IPS ("in-plane switching") displays which contain an LC layer between two substrates, wherein the two electrodes are arranged on only one of the two substrates and preferably have an intermeshed comb structure. When a voltage is applied to the electrodes, an electric field is thereby generated between them, having a significant component parallel to the LC layer. This results in a realignment of LC molecules in the layer plane.

In addition, so-called FFS (fringe field switching) displays have been reported (see inter alia s.h.jung et al, jpn.j.appl.Phys., volume 43, phase 3, 2004,1028) which contain two electrodes on the same substrate, one of which is structured in a comb-like manner and the other of which is unstructured. A strong so-called "fringe field", i.e. a strong electric field close to the edges of the electrodes, is thereby generated, and such an electric field in the whole cartridge has both a strong vertical component as well as a strong horizontal component. FFS displays have little contrast viewing angle dependence. FFS displays typically contain an LC medium with positive dielectric anisotropy, and an alignment layer, typically a polyimide, which provides planar alignment of the molecules of the LC medium.

FFS displays may operate as active matrix or passive matrix displays. In the case of active matrix displays, individual pixels are typically addressed by integrated nonlinear active elements such as transistors (e.g. thin film transistors or "TFTs"), whereas in the case of passive matrix displays individual pixels are typically addressed according to multiplexing methods as known in the art.

Furthermore, FFS displays have been disclosed (see s.h.lee et al, appl.phys.lett.73 (20), 1998, 2882-2883 and s.h.lee et al, liquid Crystals 39 (9), 2012, 1141-1148) which have similar electrode designs and layer thicknesses as FFS displays but include layers of LC media with negative dielectric anisotropy instead of LC media with positive dielectric anisotropy. LC media with negative dielectric anisotropy show a more favourable director orientation compared to LC media with positive dielectric anisotropy, which has a less tilted and more twisted orientation, as a result of which these displays have a higher transmittance. The display further comprises an alignment layer, preferably a polyimide provided on at least one substrate, which is in contact with the LC medium and induces planar alignment of LC molecules of the LC medium. These displays are also referred to as "super-bright FFS (UB-FFS)" mode displays. These displays require LC media with high reliability.

In newer types of VA displays, uniform alignment of LC molecules is limited to a plurality of relatively small domains within the LC cell. Disclination (disclination), also known as tilt domain, may exist between these domains. VA displays with inclined domains have a greater contrast and viewing angle independence of gray scale (grey scale) than conventional VA displays. In addition, this type of display is easier to produce, since no additional electrode surface treatment (e.g. by rubbing) for uniform alignment of molecules in the on-state is required. Alternatively, the preferential direction of the tilt or pretilt angle is controlled by the specific design of the electrodes.

In so-called MVA (multi-domain vertical alignment) displays, this is usually achieved by electrodes with protrusions (projections) which lead to local pretilt. The LC molecules are thereby aligned parallel to the electrode surfaces in different directions in different, defined cell areas upon application of a voltage. This achieves a "controlled" switching and prevents the formation of disturbing disclination lines. While this arrangement improves the viewing angle of the display, it results in a reduction in its light transmission. A further improvement of MVA uses protrusions on only one electrode side, while the opposite electrode has slits (slots), which improves light transmission. The slit electrode generates an inhomogeneous electric field in the LC cell upon application of a voltage, meaning that controlled switching is still achieved. To further improve the light transmission, the interval between the slit and the protrusion may be enlarged, but this in turn leads to an extension of the response time. In so-called PVA ("patterned VA") the protrusions are made completely superfluous, as the two electrodes are structured by slits on opposite sides, which results in increased contrast and improved light transmission, but which is technically difficult and makes the display more sensitive to mechanical influences ("tapping" etc.). However, for many applications, such as monitors and especially TV screens, there is a need to shorten the response time of the display and to improve the contrast and brightness (transmittance) of the display.

Another development is the so-called PS ("polymer maintenance (polymer sustained)") or PSA ("polymer maintenance alignment") displays, for which the term "polymer stabilization" is occasionally also employed. Of these, a small amount (e.g., 0.3 wt.%, typically <1 wt.%) of one or more polymerizable compounds, preferably polymerizable monomer compounds, is added to the LC medium and, after filling the LC medium into the display, is polymerized or crosslinked in situ (typically by UV photopolymerization) while optionally applying a voltage to the electrodes of the display. The polymerization is carried out at a temperature at which the LC medium exhibits a liquid crystal phase, typically at room temperature. The addition of polymerizable mesogenic or liquid crystalline compounds (also referred to as reactive mesogens or "RMs") to LC mixtures has proven particularly suitable.

Meanwhile, the PS (a) principle is being used in various conventional LC display modes. Thus, for example, PS-VA, PS-OCB, PS-IPS, PS-FFS, PS-UB-FFS and PS-TN displays are known. The polymerization of RM takes place in the case of PS-VA and PS-OCB displays, preferably under applied voltage, in the case of PS-IPS displays with or without, preferably without, applied voltage. As can be verified in the test cartridge, the PS (a) method results in a pre-tilt in the cartridge. In the case of PS-VA displays, this pre-tilt has a positive effect on the response time. For PS-VA displays, standard MVA or PVA pixel and electrode layouts may be used. However, in addition, it is also possible to cope with (a message) for example with only one structured electrode side and no protrusions, which significantly simplifies production and at the same time yields a very good contrast and a very good light transmission.

PS-VA displays are described in, for example, EP1,170626 A2, US 6,861,107, US 7,169,449, US 2004/0191428 A1, US 2006/0066793 A1 and US 2006/0103804 A1. PS-OCB displays are described, for example, in t. -J-Chen et al, jpn.j.appl.Phys.45, 2006, 2702-2704 and s.h.kim, l. -C-Chien, jpn.j.appl.Phys.43, 2004, 7643-7647. PS-IPS-displays are described, for example, in U.S. Pat. No. 3,262 and in Appl. Phys. Lett.1999, 75 (21), 3264. PS-TN-displays are described in, for example, optics Express 2004, 12 (7), 1221.

Below the layer formed by phase separation and polymerization RM inducing the pretilt angle described above, PSA displays typically comprise an alignment layer on one or both of the substrates forming the display cell, which alignment layer provides an initial alignment of the LC molecules prior to the polymer stabilization step. The alignment layer is typically applied over the electrodes (where such electrodes are present) such that it contacts the LC medium and induces initial alignment of the LC molecules. The alignment layer may comprise or consist of, for example, polyimide, which may also be rubbed or may be prepared by a photoalignment method.

Similar to the conventional LC displays described above, PSA displays may operate as either active matrix or passive matrix displays. In the case of active matrix displays, individual pixels are typically addressed by integrated non-linear active elements such as transistors (e.g., thin film transistors ("TFTs")), while in the case of passive matrix displays, addressing is typically performed by multiplexing methods as known in the art.

In particular for monitors and especially TV applications, optimization of the response time of the liquid crystal display and the contrast and brightness (and thus also the transmittance) is continuously required. PSA processes may provide key advantages herein. In particular in the case of PS-VA, PS-IPS and PS-FFS displays, a reduction in response time associated with a measurable pretilt in the test cartridge can be achieved without significant detrimental effects on other parameters.

Another problem observed in the prior art is that the use of conventional LC media in LC displays, including but not limited to PSA-type displays, often results in non-uniformities in the display, especially when the LC media is filled in display cases manufactured using the One Drop Fill (ODF) method. This phenomenon is also referred to as "ODF non-uniformity". It is therefore desirable to provide LC media that result in reduced ODF non-uniformity.

Another problem observed in the prior art is that LC media used in PSA displays, including but not limited to PSA type displays, often exhibit high viscosity and, therefore, high switching times. In order to reduce the viscosity and switching time of LC media, the addition of LC compounds having alkenyl groups has been proposed in the prior art. However, it was observed that LC media containing alkenyl compounds often show reduced reliability and stability, as well as reduced VHR, especially after exposure to UV radiation. This is a considerable disadvantage, especially for use in PSA displays, because photopolymerization of RM in PSA displays is typically carried out by exposure to UV radiation, which can lead to VHR degradation in LC media.

Furthermore, there is a great need for PSA displays and LC media and polymerizable compounds for such PSA displays, which enable high specific resistance at the same time as a large operating temperature range, short response times even at low temperatures and low threshold voltages, low pretilt angles, a large number of gray scales, high contrast and wide viewing angles, as well as VHR with high reliability and high values after UV exposure, and in the case of polymerizable compounds, low melting points and high solubility in LC host mixtures. In PSA displays for mobile applications, it is particularly desirable to have a useful LC medium that exhibits low threshold voltages and high birefringence.

A trend in displays is to achieve as fast a response time as possible for optimum motion picture quality. In this respect, media with negative dielectric isotropy have inherent disadvantages compared to LC media with positive dielectric anisotropy. On the other hand, a mixture with negative dielectric anisotropy can achieve higher transmittance in a standard FFS box layout, so its use has a positive impact on power consumption and environment. There is a need in the art to achieve both fast response times and higher transmittance. Particularly for mobile devices, there is a great need for displays with high transmittance, which enables the use of backlights with lower intensity, which consequently lead to longer battery life and therefore more sustainable products. Alternatively, a display with higher brightness, in particular with improved contrast under ambient light, may be achieved. In addition, the popularity of 8K and game monitors has led to an increase in demand for LC display panels with higher refresh rates, and thus for LC media with faster response times.

Accordingly, there remains a great need for VA, FFS or PSA displays, and LC media for VA, FFS or PSA displays optionally comprising polymerizable compounds, which do not show the above-mentioned drawbacks, or show only to a lesser extent, and have improved properties.

Disclosure of Invention

The invention is based on the following objects: a new suitable LC medium is provided which does not have the above-mentioned disadvantages or to a reduced extent.

Surprisingly, it has now been found that liquid-crystalline media having a suitably high negative Δε, a suitable phase range, and Δn and a high LTS can be achieved by using a liquid-crystalline medium comprising one or more compounds of formula I as defined below, which do not exhibit the disadvantages of the materials of the prior art or at least exhibit these disadvantages to a significantly smaller extent.

The invention relates to a liquid-crystalline medium comprising

a) One or more compounds of formula I

Wherein the method comprises the steps of

R ¹ And R is ² Identically or differently, represents H, halogen, CN, SCN, straight-chain alkyl or alkoxy having 1 to 15C atoms, straight-chain alkenyl or alkenyloxy having 2 to 15C atoms or branched-chain alkyl, alkoxy or alkenyl or alkenyloxy having 3 to 15C atoms, where one or more of these radicals CH ₂ The radicals can each be, independently of one another, substituted-C≡C-，-CF ₂ O-，-OCF ₂ -, -ch=ch-, -O-, CO-O-or-O-CO-is replaced in such a way that the O atoms are not directly connected to each other, and wherein one or more H atoms may be replaced by halogen,

A ⁰ ，A ¹ and A ² Each independently of the others represents phenylene-1, 4-diyl, wherein one or two CH groups may be replaced by N and one or more H atoms may be replaced by halogen, CN, CH ₃ ，CHF ₂ ，CH ₂ F，CF ₃ ，OCH ₃ ，OCHF ₂ Or OCF (optical clear) ₃ Alternatively, cyclohexane-1, 4-diyl, wherein one or two non-adjacent CH ₂ The radicals can be replaced independently of one another by O and/or S and one or more H atoms can be replaced by F, cyclohexene-1, 4-diyl, bicyclo [1.1.1]Pentane-1, 3-diyl, bicyclo [2.2.2]Octane-1, 4-diyl, spiro [3.3 ]]Heptane-2, 6-diyl, tetrahydropyran-2, 5-diyl or 1, 3-dioxane-2, 5-diyl,

Z ¹ and Z ² Each independently of the other, represents-CF ₂ O-，-OCF ₂ -，-CH ₂ O-,-OCH ₂ -，-CO-O-，-O-CO-，-C ₂ H ₄ -，-C ₂ F ₄ ，-CF ₂ CH ₂ -，-CH ₂ CF ₂ -，-CFHCFH-，-CFHCH ₂ -，-CH ₂ CFH-，-CF ₂ CFH-，-CFHCF ₂ -，-CH＝CH-，-CF＝CH-，-CH＝CF-, -cf=cf-, -c≡c-, or a single bond;

n represents 0,1,2 or 3, preferably 0,1 or 2, very preferably 0 or 1, particularly preferably 0; and

m represents 0,1,2 or 3, preferably 0,1 or 2, very preferably 1 or 2, in particular 1;

and

b) One or more compounds selected from the group of compounds of formulas IIA, IIB, IIC and IID

Wherein the method comprises the steps of

R ^2A ，R ^2B ，R ^2C And R is ^2D Identically or differently, represents H, straight-chain alkyl or alkoxy having 1 to 15C atoms, straight-chain alkenyl or alkenyloxy having 2 to 15C atoms or branched-chain alkyl, alkoxy or alkenyl or alkenyloxy having 3 to 15C atoms, where one or more of these radicals CH ₂ The radicals can each be, independently of one another, substituted -C≡C-，-CF ₂ O-，-OCF ₂ -, -CH=CH-, surrounded by-O-, CO-O-or-O-CO-is replaced in such a way that the O atoms are not directly connected to each other, and wherein one or more H atoms may be replaced by halogen,

L ¹ ，L ² ，L ³ and L ⁴ Each independently of the other, represents F, cl, CF ₃ Or CHF ₂ ,

Y represents H, F, cl, CF ₃ ，CHF ₂ Or CH (CH) ₃ ，

Z ² ，Z ^2B And Z ^2D Each independently of the other represents a single bond, -CH ₂ CH ₂ -,-CH＝CH-，-CF ₂ O-，-OCF ₂ -，-CH ₂ O-，-OCH ₂ -，-COO-，-OCO-，-C ₂ F ₄ -cf=cf-or-ch=chch ₂ O-,

p represents a group selected from 0,1 or 2,

q represents 0 or 1, and

v represents an integer of 1 to 6.

Compounds of formula I are known from, for example, WO 2010/099853A1 and DE 10 2010 027 099 A1.

The invention also relates to a method for preparing an LC medium as described above and below, comprising the step of mixing one or more compounds of formula I with one or more compounds of formulae IIA, IIB, IIC and/or IID and optionally with one or more chiral dopants, and optionally with one or more polymerisable compounds and optionally with further LC compounds and/or additives.

The invention also relates to the use of the LC medium according to the invention for electro-optical purposes, preferably for displays, very preferably for displays of the VA, IPS or FFS type, in particular of the UB-FFS type.

The invention also relates to the use of the LC medium according to the invention in PSA displays, in particular PSA displays comprising LC medium, for producing tilt angles in LC medium by in-situ polymerization of polymerizable Reactive Mesogens (RM) in PSA displays, preferably in an electric or magnetic field.

The invention also relates to LC displays, in particular VA, IPS, FFS or UB-FFS or PSA displays, particularly preferably FFS, UB-FFS, VA or PS-VA displays, comprising an LC medium according to the invention.

The invention also relates to the use of the LC medium according to the invention in a polymer stabilized SA-VA display, and to a polymer stabilized SA-VA display comprising the LC medium according to the invention.

According to another aspect of the invention there is provided an energy efficient display for games comprising a context defined liquid crystal medium. In a preferred embodiment, the medium for the energy efficient display of the game has a birefringence in the range of 0.125 to 0.155.

The invention also relates to a method for manufacturing an LC display as described above and below, comprising the steps of: an LC medium is filled or otherwise provided between the substrates of the display, optionally including one or more polymerizable compounds as described above and below, and optionally polymerizing the polymerizable compounds.

The LC medium according to the invention shows the following advantageous properties, in particular when used in UB-FFS displays:

excellent Low Temperature Stability (LTS)

An improved contrast of the display is provided,

High transmittance of the display

A high-definition temperature at which the light-off temperature,

a high voltage holding ratio of the current to the voltage,

low rotational viscosity

A fast-switching-over of the switching-over,

a fast response time, enabling an LCD with low power consumption to extend the battery life of the mobile device,

sufficient heat and/or UV stability, especially when used outdoors.

A suitably high birefringence combined with a fast response time for gaming applications.

LC media comprising compounds of formula I are preferred, wherein a ⁰ Represents phenylene-1, 4-diyl, wherein one or two CH groups may be replaced by N and one or more H atoms may be replaced by halogen, CN, CH ₃ ，CHF ₂ ，CH ₂ F，OCH ₃ ，OCHF ₂ ，CF ₃ Or OCF (optical clear) ₃ Instead of this.

Particularly preferred are those wherein A ⁰ The following compounds are shown

Very particular preference is given to A ⁰ Representation of

A in formula I ¹ And A ² Preferably represents phenylene-1, 4-diyl, which may also be mono-or polysubstituted by F, and cyclohexane-1, 4-diyl, cyclohexene-1, 4-diyl, tetrahydropyran-2, 5-diyl or 1, 3-dioxane-2, 5-diyl, very preferably phenylene-1, 4-diyl, which may also be mono-or polysubstituted by F, or cyclohexane-1, 4-diyl.

Z in formula I ¹ And Z ² Preferably means-CF ₂ O-，-OCF ₂ Or a single bond, very preferably a single bond.

A in formula I ¹ And A ² Particularly preferred means

Wherein L represents halogen, CF ₃ Or CN, preferably F.

Further preferred are compounds of formula I wherein R ¹ And R is ² Each independently of the others, represents H, F, or an alkyl, alkoxy, alkenyl or alkynyl group having 1 to 8, preferably 1 to 5, C atoms, each of which is optionally substituted by halogen, in particular by F.

R ¹ And R is ² Preferably represents H, optionally fluorinated alkyl or alkoxy having 1 to 7C atoms, optionally fluorinated alkenyl or alkynyl having 2 to 7 carbon atoms, optionally fluorinated cycloalkyl having 3 to 12C atoms.

Preferably, R ¹ And R is ² At least one of which is other than H, particularly preferably R ¹ And R is ² Neither is H. R is R ¹ Very particular preference is given to alkyl groups. R is R ² Furthermore, H, alkyl or fluorine are preferred. Very particular preference is given to R ¹ Is alkyl and R ² Is H or alkyl. R is R ¹ ，R ² Each independently of the others, very particularly preferably represents an unbranched alkyl radical having 1 to 5C atoms. If R is ¹ And R is ² Represents substituted alkyl, alkoxy, alkenyl or alkynyl radicals, in which R is the radical of two radicals ¹ And R is ² The total number of C atoms in (C) is preferably less than 10.

Preferred compounds of formula I are selected from the following subformulae, more preferably from the compounds of formula I-3:

wherein R is ¹ And R is ² Has the meaning indicated above, and r, s and t are independently 0,1,2,3, or 4.r is preferably 1 or 2, very preferably 2 and s and t are independently preferably 0 or 1, very preferably 0.R is R ¹ And R is ² In particular independently represent an n-alkyl group having 1 to 5C atoms.

In a first very preferred embodiment, the compounds of the formulae I-1 to I-6 are selected from the compounds of the formulae I-1a to I-6a, in particular the compounds of the formula I-3 a:

wherein R is ¹ ，R ² R and s have the meanings as defined above.

In a second very preferred embodiment, the compounds of the formulae I-1 to I-6 are selected from the compounds of the formulae I-1b to I-6b, in particular from the compounds of the formula I3-b

Wherein R is ¹ ，R ² R and s have the meanings as defined above.

In a third very preferred embodiment, the compounds of the formulae I-1 to I-6 are selected from the compounds of the formulae I-1c to I-6c, in particular the compounds of the formulae I3-c:

wherein R is ¹ ，R ² R and s have the meanings as defined above.

In a fourth very preferred embodiment, the compounds of the formulae I-1 to I-6 are selected from the compounds of the formulae I-1d to I-6d, in particular the compounds of the formula I-3 d:

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wherein R is ¹ ，R ² R and s have the meanings as defined above.

In a particularly preferred embodiment, the medium according to the invention comprises one or more compounds selected from the group consisting of the formulae I-1a to I-6a and one or more compounds selected from the group consisting of the formulae I-1b to I-6 b.

Very particularly preferably, the medium comprises one or more compounds selected from the group of compounds of the formulae I-3a, I-3b, I-3c and I-3 d:

Wherein R is ¹ ，R ² L and r have the meanings as defined above and preferably r is 0.

Furthermore, LC media comprising compounds of the following formula I are particularly preferred:

most preferred compounds of formula I include in particular one or more of the following:

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alternatively or additionally, compounds of formula I below may be used:

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preferred compounds of formulas IIA, IIB, IIC and IID are shown below:

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wherein parameter a represents 1 or 2, alkyl and alkyl each independently of the others represent a linear alkyl group having 1 to 6C atoms, and alkinyl represents a linear or branched alkenyl group having 2 to 6C atoms, and (O) represents an oxygen atom or a single bond. The alkinyl preferably represents CH ₂ ＝CH-，CH ₂ ＝CHCH ₂ CH ₂ -，CH ₃ -CH＝CH-，CH ₃ -CH ₂ -CH＝CH-，CH ₃ -(CH ₂ ) ₂ -CH＝CH-，CH ₃ -(CH ₂ ) ₃ -ch=ch-or CH ₃ -CH＝CH-(CH ₂ ) ₂ -。

Highly preferred compounds of formula IID are selected from the following subformulae:

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in a preferred embodiment, the medium comprises one or more compounds of the formula IID-10a

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Wherein the radicals and parameters present have the meanings given above under formula IID, and

R ² representation ofWherein r is 0,1,2,3,4,5 or 6 and s is 1,2 or 3.

Preferred compounds of formula IID-10a are compounds IID-10a-1 to IID-10a-14.

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Particularly preferred mixtures of the invention include one or more compounds of the formulae IIA-2, IIA-8, IIA-10, IIA-16, IIA-18, IIA-40, IIA-41, IIA-42, IIA-43, IIB-2, IIB-10, IIB-16, IIC-1, IID-4 and IID-10.

Preferred media according to the invention comprise at least one compound of the formula IIC-1,

wherein alkyl and alkyl have the above meanings.

In particular, the medium comprises one or more compounds of formula IIA-2 selected from the following subformulae:

alternatively, it is preferred that the medium comprises, in addition to the compounds of formulae IIA-2-1 to IIA-2-5, one or more compounds of formulae IIA-2a-1 to IIA-2 a-5:

in particular, the medium comprises one or more compounds of formula IIA-10 selected from the following subformulae:

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alternatively, preferably, the medium comprises, in addition to the compounds of formulae IIA-10-1 to IIA-10-5, one or more compounds of formulae IIA-10a-1 to IIA-10 a-5:

in particular, the medium comprises one or more compounds of formula IIB-10 selected from the following subformulae:

alternatively, it is preferred that the medium comprises, in addition to the compounds of formulae IIB-10-1 to IIB-10-5, one or more compounds of formulae IIB-10a-1 to IIB-10 a-5:

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the medium according to the invention preferably comprises one or more compounds of the formula III

Wherein the method comprises the steps of

R ³¹ And R is ³² Each independently of the others represents H, alkyl or alkoxy having 1 to 15C atoms, where one or more CH's in these groups ₂ The radicals being each independently of the other-C≡C-，-CF ₂ O-，-OCF ₂ -, -CH=CH-, surrounded by-O-, CO-O-or-O-CO-is replaced in such a way that the O atoms are not directly connected to each other, and wherein one or more H atoms may be replaced by halogen, A ³¹ Each occurrence is independently represented

a) 1, 4-cyclohexenylene or 1, 4-cyclohexylene, in which one or two non-adjacent CH ₂ The groups may be replaced by-O-or-S-,

b) 1, 4-phenylene in which one or two CH groups may be replaced by N, or

c) A group selected from: spiro [3.3] heptane-2, 6-diyl, 1, 4-bicyclo [2.2.2] octylene, naphthalene-2, 6-diyl, decalin-2, 6-diyl, 1,2,3, 4-tetrahydronaphthalene-2, 6-diyl, phenanthrene-2, 7-diyl and fluorene-2, 7-diyl,

wherein the radicals a), b) and c) may be monosubstituted or polysubstituted by halogen atoms,

n represents 0,1 or 2, preferably 0 or 1,

Z ³¹ independently of one another at each occurrence-CO-O-, -O-CO-, -CF ₂ O-，-OCF ₂ -，-CH ₂ O-，-OCH ₂ -，-CH ₂ -，-CH ₂ CH ₂ -，-(CH ₂ ) ₄ -，-CH＝CH-CH ₂ O-，-C ₂ F ₄ -，-CH ₂ CF ₂ -，-CF ₂ CH ₂ -, -CF=CF-, -CH=CF-, -CF=CH-, -CH=CH-, -C≡C-, or a single bond, and

L ³¹ and L ³² Each independently of the other represents F, cl, CF ₃ Or CHF ₂ Preferably H or F, most preferably F, and

w represents O or S.

The compound of formula III is preferably selected from the group consisting of compounds of formulas III-1 and/or III-2

Wherein the radicals present have the same meanings as given in the above formula III, and preferably

R ³¹ And R is ³² Each independently of the others is an alkyl, alkenyl or alkoxy group having up to 15C atoms, more preferably one or both of them represent an alkoxy group, and

L ³¹ And L ³² Each preferably represents F.

Preferably, the compound of formula III-1 is selected from the group consisting of compounds of formulas III-1-1 to III-1-11, preferably formula III-1-6

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Wherein the method comprises the steps of

alkyl and alkyl each independently of the other represent a linear alkyl group having 1 to 6C atoms, alkinyl and alkinyl each independently of the other represent a linear alkenyl group having 2 to 6C atoms, alkoxy and alkoxy each independently of the other represent a linear alkoxy group having 1 to 6C atoms, and L ³¹ And L ³² Each independently of the other represents F or Cl, preferably both F.

The compound of formula III-2 is preferably selected from the group consisting of compounds of formulas III-2-1 to III-2-10, preferably formula III-2-6,

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wherein the method comprises the steps of

Optionally, the medium comprises one or more compounds of formula IIIA-1 and/or IIIA-2

Wherein L is ³¹ And L ³² Having the same meaning as given under formula III, (O) represents O or a single bond,

R ^IIIA represents an alkyl or alkenyl group or a group Cy-C having up to 7C atoms _m H _2m+1 -,

m and n are identical or different and are 0,1,2,3,4,5 or 6, preferably 1,2 or 3, very preferably 1,

cy represents a cycloaliphatic group having 3,4 or 5 ring atoms, optionally substituted with: an alkyl or alkenyl group each having up to 3C atoms, or halogen or CN, and preferably represents cyclopropyl, cyclobutyl or cyclopentyl.

The compounds of formula IIIA-1 and/or IIIA-2 may alternatively or in addition to the compound of formula III, preferably additionally be included in the medium.

Highly preferred compounds of formulae IIIA-1 and IIIA-2 are as follows:

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wherein alkoxy represents a linear alkoxy group having 1 to 6C atoms or alternatively- (CH) ₂ ) _n F, wherein n is 2,3,4, or 5, preferably C ₂ H ₄ F。

In a preferred embodiment of the invention, the medium comprises one or more compounds of formula III-3

Wherein the method comprises the steps of

R ³¹ ，R ³² Identically or differently represents H, alkyl having 1 to 15C atomsOr alkoxy, wherein one or more of these groups are CH ₂ The radicals are optionally substituted independently of one another by-C.ident.C-, -CF ₂ O-，-OCF ₂ -，-CH＝CH-， -O-, -CO-O-or-O-CO-in such a way that the O atoms are not directly connected to each other, and wherein, in addition, one or more H atoms may be replaced by halogen.

The compound of formula III-3 is preferably selected from the compounds of formulas III-3-1 to III-3-10:

/>

Wherein R is ³² Represents alkyl having 1 to 7C atoms, preferably ethyl, n-propyl or n-butyl, or alternatively cyclopropylmethyl, cyclobutylmethyl or cyclopentylmethyl, or alternatively- (CH) ₂ ) _n F, wherein n is 2,3,4, or 5, preferably C ₂ H ₄ F。

In a preferred embodiment of the invention, the medium comprises one or more compounds of the formulae III-4 to III-6, preferably III-5,

wherein the parameters have the meanings given above, R ³¹ Preferably represents a linear alkyl group and R ³² Preferably represents alkoxy, each having 1 to 7C atoms.

In a preferred embodiment, the medium comprises one or more compounds of the formula I selected from the group consisting of the compounds of the formulae III-7 to III-9, preferably of the formula III-8,

In a preferred embodiment, the medium comprises one or more compounds of formula IV,

wherein the method comprises the steps of

R ⁴¹ Represents unsubstituted alkyl having 1 to 7C atoms or unsubstituted alkenyl having 2 to 7C atoms, preferably n-alkyl, particularly preferably having 2,3,4 or 5C atoms, and

R ⁴² represents unsubstituted alkyl having 1 to 7C atoms or unsubstituted alkoxy having 1 to 6C atoms (each preferably having 2 to 5C atoms), unsubstituted alkenyl having 2 to 7C atoms, preferably having 2,3 or 4C atoms, more preferably vinyl or 1-propenyl, in particular vinyl.

The compound of formula IV is preferably selected from compounds of formulae IV-1 to IV-4,

wherein the method comprises the steps of

alkyl and alkyl', independently of each other, represent an alkyl group having 1 to 7C atoms, preferably having 2 to 5C atoms,

alkinyl represents an alkenyl group having 2 to 5C atoms, preferably having 2 to 4C atoms, particularly preferably 2C atoms,

alkinyl' denotes alkenyl having 2 to 5C atoms, preferably having 2 to 4C atoms, particularly preferably having 2 to 3C atoms, and

alkoxy means an alkoxy group having 1 to 5C atoms, preferably having 2 to 4C atoms.

The compound of formula IV-1 is preferably selected from compounds of formulae IV-1-1 to IV-1-5:

the compound of formula IV-2 is preferably selected from the group consisting of compounds of formulas IV-2-1 and IV-2-2

The compound of formula IV-3 is preferably selected from the group consisting of compounds of formulas IV-3-1 and IV-3-2

Wherein alkyl has the meaning defined above.

The compounds of formulae IV-3-1 and IV-3-2 are preferably selected from the following compounds:

very preferably, the medium according to the invention comprises compounds of the formula IV-4, in particular compounds selected from the group consisting of the formulae IV-4-1 to IV-4-3

In one embodiment, the medium according to the invention comprises a combination of one or more compounds of formula I selected from the group consisting of compounds of formulas I-1 to I-4 and one or more compounds selected from the group consisting of compounds of formulas IA-1 to IA-9:

Wherein alkyl represents methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl or n-pentyl.

The liquid-crystalline medium preferably additionally comprises one or more compounds of the formula IVa,

wherein the method comprises the steps of

R ⁴¹ And R is ⁴² Each independently of the others represents a straight-chain alkyl, alkoxy, alkenyl, alkoxyalkyl or alkoxy radical having up to 12C atoms, and

Z ⁴ represents a single bond, -CH ₂ CH ₂ -，-CH＝CH-，-CF ₂ O-，-OCF ₂ -，-CH ₂ O-，

-OCH ₂ -,-COO-，-OCO-，-C ₂ F ₄ -，-C ₄ H ₈ -，-CF＝CF-.

Preferred compounds of formula IVa are shown below:

wherein the method comprises the steps of

The alkyl and alkyl each independently represent a straight chain alkyl group having 1 to 6C atoms.

The medium according to the invention preferably comprises at least one compound of the formula IVa-1 and/or IVa-2.

The proportion of the compounds of the formula IVa in the overall mixture is preferably less than 5% by weight, very preferably less than 2% by weight.

Preferably, the medium comprises one or more compounds of the formulae IVb-1 to IVb-3

Wherein the method comprises the steps of

alkyl and alkyl each independently of the other represent a linear alkyl radical having 1 to 6C atoms, and

each of alkinyl and alkinyl, independently of the other, represents a straight-chain alkenyl group having 2 to 6C atoms.

Of the compounds of the formulae IVb-1 to IVb-3, compounds of the formula IVb-2 are particularly preferred.

Particularly preferred biphenyls are

Wherein alkyl represents an alkyl group having 1 to 6C atoms and preferably represents an n-propyl group. The medium according to the invention particularly preferably comprises one or more compounds of the formulae IVb-1-1 and/or IVb-2-3.

In a preferred embodiment, the medium according to the invention comprises one or more compounds of the formula V

Wherein the method comprises the steps of

R ⁵¹ ，R ⁵² Represents alkyl having 1 to 7C atoms, alkoxy having 1 to 7C atoms, or alkoxyalkyl, alkenyl or alkenyloxy having 2 to 7C atoms,identically or differently, denote

Z ⁵¹ ，Z ⁵² Each independently of the other represents-CH ₂ -CH ₂ -，-CH ₂ -O-, -ch=ch-, -c≡c-, -COO-, or a single bond, and

n is 1 or 2, and the number of the N is 1 or 2,

wherein the compound of formula CL is excluded.

The compound of formula V is preferably selected from compounds of formulae V-1 to V-16:

wherein R is ⁵¹ And R is ⁵² Has the meaning indicated by the above formula V.

R ⁵¹ And R is ⁵² Preferably each independently of the other represents a straight-chain alkyl group having 1 to 7C atoms or an alkenyl group having 2 to 7C atoms.

Preferred media comprise one or more compounds of the formulae V-1, V-5, V-6, V-8,V-9,V-10, V-11, V-12, V-14, V-15, and/or V-16, very particularly preferably V-5 or V-6.

Preferably, the medium according to the invention comprises one or more compounds of formula CL

Wherein the method comprises the steps of

R ^L Represents H, a linear or branched alkyl or alkoxy radical having 1 to 15C atoms, or a linear or branched alkenyl radical having 2 to 15C atoms, wherein one or more of these radicals CH ₂ The radicals can each be, independently of one another, substituted -C≡C-，-CF ₂ O-，-OCF ₂ -, -ch=ch-, -O-, CO-O-or-O-CO-is replaced in such a way that the O atoms are not directly connected to each other, and wherein, in addition, one or more H atoms may be replaced by halogen,

X ^L represents F, cl, CN, CHF ₂ ，CF ₃ ，OCF ₃ Or identically or differently, have R ^L In one of the meanings of (a),

Y ^L represents H, F, cl or CH ₃ 。

The compound of formula CL is preferably selected from the group of compounds of formulae CL-1, CL-2 and CL-3

Wherein the method comprises the steps of

R ^L1 And R is ^L2 Identically or differently having the meanings given above for formula I, and preferably denote alkyl or alkenyl radicals having 1 to 7C atoms or 2 to 7C atoms, respectively, where CH ₂ The groups may be replaced by cyclopropane-1, 2-diyl.

Highly preferred compounds of formula I are selected from the group consisting of compounds of formulas CL-3-1 to CL-3-12:

/>

in a preferred embodiment, the medium according to the invention comprises compound CL-3-1.

In a preferred embodiment of the invention, the medium additionally comprises one or more compounds of the formulae VI-1 to VI-21, preferably of the formula VI-4:

/>

wherein R is ⁶ Represents a linear alkyl or alkoxy group having 1 to 6C atoms, (O) represents-O-or a single bond, and m is 0,1,2,3,4,5 or 6 and n is 0,1,2,3 or 4.

R preferably represents methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy, butoxy, pentoxy.

In a preferred embodiment of the invention, the medium additionally comprises one or more compounds of the formulae VII-1 to VII-9

Wherein the method comprises the steps of

R ⁷ Represents a linear alkyl or alkoxy group having 1 to 6C atoms, or a linear alkenyl group having 2 to 6C atoms, and

w is an integer of 1 to 6.

Additional preferred embodiments are set forth below.

a) Liquid-crystalline medium comprising at least one compound of the formulae Z-1 to Z-7,

wherein R and alkyl have the meanings indicated above for formula III.

b) Preferred liquid-crystalline media according to the invention comprise one or more substances comprising tetrahydronaphthyl or naphthyl units, for example compounds of the formulae N-1 to N-5,

wherein R is ^1N And R is ^2N Each independently of the other has a meaning for R ^2A The indicated meanings preferably denote linear alkyl, linear alkoxy or linear alkenyl, and

Z ¹ and Z ² Each independently of the other represents-C ₂ H ₄ -，-CH＝CH-，-(CH ₂ ) ₄ -，-(CH ₂ ) ₃ O-，-O(CH ₂ ) ₃ -，-CH＝CHCH ₂ CH ₂ -，-CH ₂ CH ₂ CH＝CH-，-CH ₂ O-，-OCH ₂ -，-COO-，-OCO-，-C ₂ F ₄ -，-CF＝CF-，-CF＝CH-，-CH＝CF-，-CF ₂ O-，-OCF ₂ -，-CH ₂ -or a single bond.

c) Preferred mixtures comprise one or more compounds selected from the group consisting of difluorodibenzochroman compounds of formula BC, chromans of formula CR, and fluorophenanthrenes of formulae PH-1 and PH-2,

/>

wherein R is ^B1 ，R ^B2 ，R ^CR1 ，R ^CR2 ，R ¹ ，R ² Each independently of the other has R ^2A Meaning of (c). c is 0,1 or 2.R is R ¹ And R is ² Preferably, independently of one another, alkyl or alkoxy having 1 to 6C atoms are represented.

Particularly preferred compounds of the formulae BC and CR are the compounds BC-1 to BC-7 and CR-1 to CR-5,

/>

Wherein the method comprises the steps of

Very particular preference is given to mixtures comprising one, two or three compounds of the formulae BC-2, BF-1 and/or BF-2.

d) Preferred mixtures comprise one or more indane compounds of formula In,

wherein the method comprises the steps of

R ¹¹ ，R ¹² And R is ¹³ Each independently of the others represents a straight-chain alkyl, alkoxy, alkoxyalkyl or alkenyl radical having 1 to 6C atoms,

R ¹² and R is ¹³ Alternatively, halogen, preferably F,

representation of

i represents 0,1 or 2.

Preferred compounds of formula In are compounds of formulae In-1 to In-16 described below:

/>

particularly preferred are compounds of the formulae In-1, in-2, in-3 and In-4.

e) Preferred mixtures additionally comprise one or more compounds of the formulae L-1 to L-5,

/>

wherein the method comprises the steps of

R，R ¹ And R is ² Each independently of the other has the meaning given above for R in IIA ^2A The meaning stated, and alkyl denote alkyl having 1 to 6C atoms. The parameter s represents 1 or 2.

The compounds of the formulae L-1 to L-9 are preferably used in concentrations of 5 to 15% by weight, in particular 5 to 12% by weight and very particularly preferably 8 to 10% by weight.

f) Preferred mixtures additionally comprise one or more compounds of the formula IIA-Y

Wherein R is ¹¹ And R is ¹² Having the above-mentioned meaning for R in formula IIA ^2A One of the meanings given, and L ¹ And L ² F or Cl are identically or differently represented,

preferred compounds of formula IIA-Y are selected from the following subformulae

/>

Wherein, alkyl and Alkyl each independently of the other represent a linear Alkyl group having 1 to 6C atoms, alkoxy represents a linear Alkoxy group having 1 to 6C atoms, alkonyl and alkinyl each independently of the other represent a linear Alkenyl group having 2 to 6 carbon atoms, and O represents an oxygen atom or a single bond. Alkenyl and Alkenyl preferably represent CH ₂ ＝CH-，CH ₂ ＝CHCH ₂ CH ₂ -，CH ₃ -CH＝CH-，CH ₃ -CH ₂ -CH＝CH-，CH ₃ -(CH ₂ ) ₂ -CH＝CH-，CH ₃ -(CH ₂ ) ₃ -ch=ch-or CH ₃ -CH＝CH-(CH ₂ ) ₂ -。

Particularly preferred compounds of formula IIA-Y are selected from the following subformulae:

wherein Alkoxy and Alkoxy have the meanings defined above and preferably represent methoxy, ethoxy, n-propyloxy, n-butyloxy or n-pentyloxy.

Preferably, the medium according to the invention comprises a compound selected from the group of compounds of formulae ST-1 to ST-18, very preferably of formula ST-3:

/>

wherein the method comprises the steps of

R ^ST Represents H, alkyl or alkoxy having 1 to 15C atoms, where, in addition, one or more CH's in these radicals ₂ The radicals can each be, independently of one another, substituted by-C.ident.C-, -CF ₂ O-，-OCF ₂ -，-CH＝CH-，

-O-, -CO-O-, -O-CO-is replaced in such a way that O atoms are not directly connected to each other, and wherein, in addition, one or more H atoms may be replaced by halogen,

At each occurrence, identically or differently, represent +.>

Z ^ST Each independently of the other represents-CO-O-, -O-CO-, -CF ₂ O-，-OCF ₂ -，-CH ₂ O-，-OCH ₂ -，-CH ₂ -，-CH ₂ CH ₂ -，-(CH ₂ ) ₄ -，-CH＝CH-，-CH ₂ O-，-C ₂ F ₄ -，-CH ₂ CF ₂ -，-CF ₂ CH ₂ -, -cf=cf-, -ch=cf-, -cf=ch-, -ch=ch-, -c≡c-, or a single bond,

L ¹ and L ² Each independently of the other represents F, cl, CH ₃ ，CF ₃ Or CHF ₂ ，

p represents a group selected from 0,1 or 2,

q represents 1,2,3,4,5,6,7,8,9 or 10.

Of the compounds of the formula ST, particular preference is given to compounds of the formula ST-3, in particular:

where n=1, 2,3,4,5,6 or 7, preferably n

＝3

Where n=1, 2,3,4,5,6 or 7, preferably n

＝3

Wherein n=1, 2,3,4,5,6 or 7, preferably n=1 or 7

/>

In the compounds of the formulae ST-3a and ST-3b, n preferably denotes 3. In the compounds of the formula ST-2a, n preferably represents 7.

Very particularly preferred mixtures according to the invention comprise one or more stabilizers selected from the group consisting of the compounds of the formulae ST-2a-1, ST-3b-1, ST-8-1, ST-9-1 and ST-12:

/>

preferably, the medium comprises one or more compounds of formula S

Wherein the method comprises the steps of

Ar represents a methylene group or an aromatic hydrocarbon group having 6 to 40C atoms or a heteroaromatic hydrocarbon group having 4 to 40C atoms; preferably an aromatic hydrocarbon group having 6 to 40C atoms;

sp represents a spacer group;

R ^S represents H, an alkyl group having 1 to 12C atoms or an alkenyl group having 2 to 12 carbon atoms;

Z ^S represents-O-, -C (O) O-, -CH ₂ ) _z -or- (CH) ₂ ) _z O-, or a single bond;

HA representation/>

R ^H Represents H, O ^· ，CH ₃ OH OR OR ^S ；

R ^S1 ，R ^S2 ，R ^S3 And R is ^S4 Identically or differently represents alkyl having 1 to 6C atoms, preferably having 1 to 3C atoms, very preferably CH ₃ ；

G represents H or R ^S Or a group Z ^S -HA；

z is an integer from 1 to 6, and

q is 2,3 or 4, preferably 3 or 4.

In formula S, aryl represents an aromatic or heteroaromatic hydrocarbon radical having 4 to 40C atoms, including one, two, three or four aromatic rings comprising condensed rings which may be directly linked or linked through an alkylene linking group having 1 to 12 carbon atoms, wherein one or more H atoms are optionally replaced by an alkyl or alkoxy radical having 1 to 6C atoms or an alkenyl radical having 2 to 6 carbon atoms, or are optionally substituted by CN, CF ₃ Or halogen substitution, and wherein one or more CH ₂ The radicals can each be replaced independently of one another by-O-, -S-, -NH-, -N (C) ₁ -C ₄ -alkyl) -, -CO-O-, -O-CO-O-, -ch=ch-, or-c≡c-is substituted in such a manner that O or S atoms are not directly connected to each other.

Preferred aryl groups are benzene, naphthalene, anthracene, biphenyl, m-terphenyl, p-terphenyl and (phenylalkyl) benzene, wherein the alkyl group is a straight chain alkyl group having 1 to 12C atoms.

In a preferred embodiment, the medium according to the invention comprises a compound of formula S, wherein the parameter q is 3 and G represents the group Z ^S -HA。

In another preferred embodiment, the medium according to the invention comprises a compound of formula S, wherein the parameter q is 4 and G represents H or R ^S 。

The compound of formula S is preferably selected from compounds of formulas S-1, S-2 and S-3:

wherein R is ^H Having the meanings given above and preferably representing H or o,

sp represents the spacer group identically or differently at each occurrence, and

w represents a linear or branched, optionally unsaturated, alkylene radical having 1 to 12C atoms, in which one or more non-adjacent-CH ₂ The group may be replaced by-O-.

Preferred compounds of formula S-1 are selected from compounds of formula S-1-1:

wherein R is ^H Having the meanings given above and preferably representing H or o, and n is an integer from 0 to 12, preferably 5,6,7,8 or 9, very preferably 7.

Preferred compounds of formula S-2 are selected from compounds of formula S-2-1:

wherein R is ^H Having the meanings given above and preferably representing H or O, and n2, identical or different at each occurrence, preferably identical, is an integer from 1 to 12, preferably 2,3,4,5, or 6, very preferably 3, and R ^S And on each occurrence identically or differently, preferably identically, represents an alkyl group having 1 to 6C atoms, preferably an n-butyl group.

Preferred compounds of formula S-3 are selected from compounds of formula S-3-1:

The compounds of the formulae S and ST-1 to ST-18 are preferably each present in the liquid-crystal mixtures according to the invention in an amount of from 0.005 to 0.5%, based on the mixture.

If the mixture according to the invention comprises two or more compounds of the formulae S and ST-1 to ST-18, the concentration increases accordingly to 0.01 to 1% in the case of the two compounds, based on the mixture.

However, the total proportion of the compounds of the formulae S and ST-1 to ST-18 should not exceed 2%, based on the mixture according to the invention.

The liquid-crystalline medium according to the invention (also referred to herein as liquid-crystalline host mixture) is suitable for use in polymer-stabilized displays. To this end, the medium according to the invention optionally comprises one or more polymerizable compounds of formula P:

P-Sp-A ¹ -(Z ¹ -A ² ) _z -R P

wherein each occurrence is the same or different independently of the other

P represents a polymerizable group and is preferably a polymerizable group,

sp represents a spacer group or a single bond,

A ¹ 、A ² represents an aromatic, heteroaromatic, cycloaliphatic or heterocyclic radical, preferably having from 4 to 25 ring atoms, which may also contain condensed rings, and which is unsubstituted or monosubstituted or polysubstituted by L,

Z ¹ represents-O-, -S-, -CO-, -CO-O-, -and-O-CO-, -O-CO-O-, -OCH ₂ -，-CH ₂ O-，-SCH ₂ -，-CH ₂ S-,-CF ₂ O-，-OCF ₂ -，-CF ₂ S-，-SCF ₂ -，-(CH ₂ ) _n1 -，-CF ₂ CH ₂ -，-CH ₂ CF ₂ -，-(CF ₂ ) _n1 -，-CH＝CH-，-CF＝CF-，-CH＝CF-，-CF＝CH-，-C≡C-，-CH＝CH-CO-O-，-O-CO-CH＝CH-，-CH ₂ -CH ₂ -CO-O-，-O-CO-CH ₂ -CH ₂ -，-CR ⁰ R ⁰⁰ -, or a single bond,

R ⁰ ，R ⁰⁰ represents H or an alkyl group having 1 to 12C atoms,

r represents H, L, or P-Sp-,

l represents F, cl, -CN, P-Sp-, or a straight, branched or cyclic alkyl group having 1 to 25C atoms, wherein one or more non-adjacent CH ₂ The radicals are optionally interrupted by-O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-is replaced in such a manner that O and/or S atoms are not directly connected to each other, and wherein one or more H atoms are each optionally replaced by P-Sp-, F or Cl,

z is 0,1,2 or 3, and

n1 is 1,2,3 or 4.

The term "reliability" as used herein means the quality of the performance of the display during time and under different stress loads (stress loads), such as light load, temperature, humidity, voltage, and includes display effects such as image sticking (face and line image sticking), non-uniformity (mura), smudge (yocore), etc., which are known to those skilled in the art of LC displays. As a standard parameter for classifying reliability, a Voltage Holding Ratio (VHR) value, which is a measure for maintaining a constant voltage in a test display, is generally used. Among other factors, high VHR is a precondition for high reliability of LC media.

The term "PSA" is used hereinafter when referring generally to polymer sustained alignment type displays, and the term "PS" is used when referring to specific display modes (e.g., PS-VA, PS-TN, etc.), unless otherwise indicated.

As used herein, the terms "active layer" and "switchable layer" refer to a layer comprising one or more molecules (e.g., LC molecules) having structural and optical anisotropy that change their orientation when subjected to an external stimulus, such as an electric or magnetic field, in an electro-optic display, such as an LC display, which results in a change in the transmittance of the layer for polarized or unpolarized light.

As used herein, the terms "tilt" and "tilt angle" are understood to mean the tilt alignment of LC molecules of the LC medium relative to the cell surface in an LC display (here preferably a PSA display). The tilt angle here means the average angle (< 90 °) between the longitudinal molecular axis of the LC molecules (LC director) and the plane-parallel outer plates forming the LC cell. Where a low value of the tilt angle (i.e. a large deviation from the 90 angle) corresponds to a large tilt. Suitable methods of measuring tilt angle are given in the examples. The tilt angle values disclosed in the context relate to such measurement methods, unless otherwise indicated.

As used herein, the terms "reactive mesogen" and "RM" are understood to mean a compound comprising a mesogen or liquid crystal backbone, and one or more functional groups suitable for polymerization attached thereto, and said functional groups are also referred to as "polymerizable groups" or "P".

The term "polymerizable compound" as used herein is understood to mean a polymerizable monomer compound unless otherwise indicated.

As used herein, the term "low molecular weight compound" is understood to mean a compound that is monomeric and/or is not prepared by polymerization, as opposed to "polymeric compound" or "polymer".

As used herein, the term "non-polymerizable compound" is understood to mean a compound that does not contain functional groups suitable for polymerization under the conditions typically applied to RM polymerization.

As used herein, the term "mesogenic group" is known to those skilled in the art and described in the literature, and refers to a group that substantially contributes to the creation of a Liquid Crystal (LC) phase in a low molecular weight or polymeric species due to the anisotropy of its attractive and repulsive interactions. The compound containing mesogenic groups (mesogenic compound) does not necessarily have to have an LC phase per se. The mesogenic compounds may also exhibit LC phase behaviour only after mixing with other compounds and/or after polymerization. Typical mesogenic groups are for example rigid rod-like or disk-like units. The terms and definitions used in connection with mesogenic or LC compounds are given in pureappl. Chem.2001, 73 (5), 888 and C.Tschierske, G.Pelzl, S.Diele, angew.Chem.2004,116,6340-6368.

As used herein, the terms "optically active" and "chiral" are synonymous with material, which can induce a helical pitch in a nematic host material, also referred to as a "chiral dopant".

As used herein, the term "spacer group" (also referred to hereinafter as "Sp") is known to those skilled in the art and is described in the literature, see for example pureappl. Chem.2001, 73 (5), 888 and C.Tschierske, G.Pelzl, S.Diele, angew.Chem.2004,116,6340-6368. As used herein, the term "spacer group" or "spacer group" means a flexible group, e.g., it is an alkylene group that connects the mesogenic group and the polymerizable group(s) in the polymerizable mesogenic compound.

Also, in the compounds of formula I, the spacer groups link the central hydrocarbyl group to the photoactive, stable, sterically hindered amine functional group.

In the context of the present context, it is intended that,represents a trans-1, 4-cyclohexylidene ring.

At a groupThe single bond shown between the two ring atoms may be attached to any free position of the benzene ring.

"organic group" in this context means a carbon or hydrocarbon group.

"carbon group" means a mono-or polyvalent organic group containing at least one carbon atom, wherein the group contains no other atoms (e.g., -C≡C-) or optionally one or more other atoms, such as N, O, S, B, P, si, se, as, te or Ge (e.g., carbonyl, etc.). The term "hydrocarbyl group" means a carbon group that additionally contains one or more H atoms and optionally one or more heteroatoms, such as N, O, S, B, P, si, se, as, te or Ge.

"halogen" means F, cl, br or I, preferably F or Cl.

-CO-, -C (=o) -and-C (O) -represent carbonyl groups, i.e.

The carbon or hydrocarbon group may be a saturated or unsaturated group. The unsaturated group is, for example, an aryl, alkenyl or alkynyl group. The carbon or hydrocarbon group having more than 3C atoms may be linear, branched, and/or cyclic and may also contain spiro or fused rings.

The terms "alkyl", "aryl", "heteroaryl" and the like also include multivalent groups such as alkylene, arylene, heteroarylene and the like.

The term "aryl" means an aromatic carbon group or a group derived therefrom. The term "heteroaryl" denotes an "aryl" group as defined above comprising one or more heteroatoms (preferably selected from N, O, S, se, te, si and Ge).

Preferred carbon and hydrocarbon groups are optionally substituted, straight-chain, branched or cyclic alkyl, alkenyl, alkynyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy and alkoxycarbonyloxy having from 1 to 40, preferably from 1 to 20, very preferably from 1 to 12, C atoms, optionally substituted aryl or aryloxy having from 5 to 30, preferably from 6 to 25, C atoms, or optionally substituted alkylaryl, arylalkyl, alkylaryl, arylalkyloxy, arylcarbonyl, aryloxycarbonyl, arylcarbonyloxy and aryloxycarbonyloxy having from 5 to 30, preferably from 6 to 25, C atoms, wherein one or more C atoms may also be replaced by heteroatoms, preferably selected from N, O, S, se, te, si and Ge.

Further preferred carbon and hydrocarbon groups are C ₁ -C ₂₀ Alkyl, C ₂ -C ₂₀ Alkenyl, C ₂ -C ₂₀ Alkynyl, C ₃ -C ₂₀ Allyl, C ₄ -C ₂₀ Alkyldienyl, C ₄ -C ₂₀ Polyalkenyl, C ₆ -C ₂₀ Cycloalkyl, C ₄ -C ₁₅ Cycloalkenyl, C ₆ -C ₃₀ Aryl, C ₆ -C ₃₀ Alkylaryl, C ₆ -C ₃₀ Aralkyl, C ₆ -C ₃₀ Alkyl aryloxy, C ₆ -C ₃₀ Arylalkoxy, C ₂ -C ₃₀ Heteroaryl, C ₂ -C ₃₀ A heteroaryloxy group.

Particularly preferred is C ₁ -C ₁₂ Alkyl, C ₂ -C ₁₂ Alkenyl, C ₂ -C ₁₂ Alkynyl, C ₆ -C ₂₅ Aryl and C ₂ -C ₂₅ Heteroaryl groups.

Further preferred carbon and hydrocarbon groups are those havingA linear, branched or cyclic alkyl radical of 1 to 20, preferably 1 to 12, C atoms, which is unsubstituted or mono-or polysubstituted by F, cl, br, I or CN, and in which one or more of the non-adjacent CH's are present ₂ The radicals can each, independently of one another, be substituted by-C (R ^x )＝C(R ^x )-、-C≡-、-N(R ^x ) -, -O-, -S-; -CO- -CO-O-, -O-CO-, -O-CO-O-is replaced in such a way that the O and/or S atoms are not directly connected to each other.

R ^x Preferably H, F, cl, CN, a straight, branched or cyclic alkyl chain having from 1 to 25C atoms, wherein in addition, one or more non-adjacent C atoms may be replaced by-O-, -S-, -CO-, -CO-O-, -O-CO-O-replacement, and wherein one or more H atoms may be replaced by F or Cl or represent an optionally substituted aryl or aryloxy group having 6 to 30C atoms or an optionally substituted heteroaryl or heteroaryloxy group having 2 to 30C atoms.

Preferred alkyl groups are, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, 2-methylbutyl, n-pentyl, sec-pentyl, cyclopentyl, n-hexyl, cyclohexyl, 2-ethylhexyl, n-heptyl, cycloheptyl, n-octyl, cyclooctyl, n-nonyl, n-decyl, n-undecyl, n-dodecyl, trifluoromethyl, perfluoro-n-butyl, 2-trifluoroethyl, perfluoro-octyl, perfluorohexyl and the like.

Preferred alkenyl groups are, for example, ethenyl, propenyl, butenyl, pentenyl, cyclopentenyl, hexenyl, cyclohexenyl, heptenyl, cycloheptenyl, octenyl, cyclooctenyl and the like.

Preferred alkynyl groups are, for example, ethynyl, propynyl, butynyl, pentynyl, hexynyl, octynyl and the like.

Preferred alkoxy groups are, for example, methoxy, ethoxy, 2-methoxyethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, 2-methylbutoxy, n-pentoxy, n-hexoxy, n-heptoxy, n-octoxy, n-nonoxy, n-decoxy, n-undecoxy, n-dodecoxy and the like.

Preferred amino groups are, for example, dimethylamino, methylamino, methylphenylamino, phenylamino, and the like.

Aryl and heteroaryl groups may be monocyclic or polycyclic, i.e., they may contain one ring (e.g., phenyl) or two or more rings, which may also be fused (e.g., naphthyl) or covalently bonded (e.g., biphenyl), or comprise a combination of fused and linked rings. Heteroaryl contains one or more heteroatoms, preferably selected from O, N, S and Se.

Particularly preferred are mono-, bi-or tricyclic aryl groups having 6 to 25C atoms and mono-, bi-or tricyclic heteroaryl groups having 5 to 25 ring atoms, which optionally contain fused rings and are optionally substituted. Further preferred are 5-, 6-or 7-membered aryl and heteroaryl groups, wherein in addition one or more CH groups may be replaced by N, S or O in such a way that O atoms and/or S atoms are not directly connected to each other.

Preferred aryl groups are, for example, phenyl, biphenyl, terphenyl, [1,1':3',1 ] "]-terphenyl-2' -yl, naphthyl, anthracenyl, binaphthyl, phenanthryl, 9, 10-dihydro-phenanthryl, pyrene, dihydropyrene,Perylene, tetracene, pentacene, benzopyrene, fluorene, indene, indenofluorene, spirobifluorene (spirobifluorene), and the like.

Preferred heteroaryl groups are, for example, 5-membered rings, such as pyrrole, pyrazole, imidazole, 1,2, 3-triazole, 1,2, 4-triazole, tetrazole, furan, thiophene, selenophene, oxazole, isoxazole, 1, 2-thiazole, 1, 3-thiazole, 1,2, 3-oxadiazole, 1,2, 4-oxadiazole, 1,2, 5-oxadiazole, 1,3, 4-oxadiazole, 1,2, 3-thiadiazole, 1,2, 4-thiadiazole, 1,2, 5-thiadiazole, 1,3, 4-thiadiazole, 6-membered rings, such as pyridine, pyridazine, pyrimidine, pyrazine, 1,3, 5-triazine, 1,2, 4-triazine, 1,2, 3-triazine, 1,2,4, 5-tetrazine, 1,2,3, 4-tetrazine, 1,2,3, 5-tetrazine or fused groups, such as indole, isoindole, indolizine, indazole, benzimidazole, benzotriazole, purine, naphthazole, phenanthroimidazole, pyridoimidazole, pyrazinoimidazole, quinoxalinoimidazole, benzoxazole, naphthazole, anthraoxazole, phenanthrooxazole, isoxazole, benzothiazole, benzofuran, isobenzofuran, dibenzofuran, quinoline, isoquinoline, pteridine, benzo-5, 6-quinoline, benzo-6, 7-quinoline, benzo-7, 8-quinoline, benzisoquinoline, acridine, phenothiazine, phenoxazine, benzopyridazine, benzopyrimidine, quinoxaline, phenazine, naphthyridine, azacarbazole, benzocarboline, phenanthridine, phenanthroline, thieno [2,3b ] thiophene, thieno [3,2b ] thiophene, dithienothiophene, isobenzothiophene, dibenzothiophene, benzothiophene, benzothiadiazole, or a combination of these groups.

The aryl and heteroaryl groups mentioned in the context may also be substituted by alkyl, alkoxy, thioalkyl, fluoro, fluoroalkyl or other aryl or heteroaryl groups.

(non-aromatic) alicyclic groups and heterocyclic groups comprise both saturated rings, i.e. rings containing only single bonds, and partially unsaturated rings, i.e. those which may also contain multiple bonds. The heterocyclic ring contains one or more heteroatoms, preferably selected from Si, O, N, S and Se.

The (non-aromatic) alicyclic and heterocyclic groups may be monocyclic, i.e. contain only one ring (e.g. cyclohexane), or polycyclic, i.e. contain multiple rings (e.g. decalin or bicyclooctane). Saturated groups are particularly preferred. Preference is furthermore given to mono-, bi-or tricyclic groups having 5 to 25 ring atoms which optionally contain fused rings and are optionally substituted. Further preferred are 5-, 6-, 7-or 8-membered carbocyclic groups in which, in addition, one or more C atoms may be replaced by Si and/or one or more CH groups may be replaced by N and/or one or more non-adjacent CH groups ₂ The groups may be replaced by-O-and/or-S-.

Preferred cycloaliphatic and heterocyclic groups are, for example, 5-membered groups, such as cyclopentane, tetrahydrofuran, tetrahydrothiophene, pyrrolidine; 6-membered radicals, such as cyclohexane, silacyclohexane (silane), cyclohexene, tetrahydropyran, tetrahydrothiopyran, 1, 3-dioxane, 1, 3-dithiane, piperidine; 7-membered groups such as cycloheptane; and condensed groups such as tetrahydronaphthalene, decalin, indane, bicyclo [1.1.1] pentane-1, 3-diyl, bicyclo [2.2.2] octane-1, 4-diyl, spiro [3.3] heptane-2, 6-diyl, octahydro-4, 7-methanoindan-2, 5-diyl.

Preferred substituents are, for example, solubility promoting groups, such as alkyl or alkoxy groups; electron withdrawing groups such as fluorine, nitro or nitrile; or substituents for increasing the glass transition temperature (Tg) of the polymer, in particular bulky groups such as tert-butyl or optionally substituted aryl.

Preferred substituents, hereinafter also referred to as "L ^S ", is, for example, F, cl, br, I, -CN, -NO ₂ 、-NCO、-NCS、-OCN、-SCN、-C(＝O)N(R ^x ) ₂ 、-C(＝O)Y ¹ 、-C(＝O)R ^x 、-N(R ^x ) ₂ Straight or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy groups having 1 to 25C atoms, wherein one or more H atoms may optionally be replaced by F or Cl, optionally substituted silyl (silyl) having 1 to 20 Si atoms, or optionally substituted aryl having 6 to 25, preferably 6 to 15C atoms.

Wherein R is ^x Represents H, F, cl, CN, or a linear, branched or cyclic alkyl radical having 1 to 25C atoms, in which one or more non-adjacent CH ₂ The radicals are optionally substituted by-O-, -S-, -CO-, -CO-O-, -O-CO-, O-CO-O-is replaced in such a way that the O-and/or S-atoms are not directly linked to one another, and wherein one or more H atoms are each optionally replaced by F, cl, P-or P-Sp-, and

Y ¹ represents halogen.

"substituted silyl or aryl" preferably means that it is substituted with halogen, -CN, R ⁰ 、-OR ⁰ 、-CO-R ⁰ 、-CO-O-R ⁰ 、-O-CO-R ⁰ or-O-CO-O-R ⁰ Substitution, wherein R ⁰ Represents H or an alkyl group having 1 to 20C atoms.

Particularly preferred substituents L are, for example, F, cl, CN, NO ₂ 、CH ₃ 、C ₂ H ₅ 、OCH ₃ 、OC ₂ H ₅ 、COCH ₃ 、COC ₂ H ₅ 、COOCH ₃ 、COOC ₂ H ₅ 、CF ₃ 、OCF ₃ 、OCHF ₂ 、OC ₂ F ₅ In addition, phenyl is also present.

A ¹ And A ² Very preferred representationWherein L has one of the above meanings and r represents 0,1,2,3 or 4, in particular

Representation->/>

The polymerizable group P is a group suitable for polymerization (e.g., radical or ionic chain polymerization, addition polymerization or condensation polymerization) or a group suitable for polymer-analogous reactions (e.g., addition or condensation on the polymer backbone). Particularly preferred are groups for chain polymerization, in particular those comprising a c=c double bond or-c≡c-triple bond, and groups suitable for ring-opening polymerization, such as oxetanyl or epoxy groups.

Preferred groups P are selected from the group consisting of: CH (CH) ₂ ＝CW ¹ -CO-O-、CH ₂ ＝CW ¹ -CO-、

CH ₂ ＝CW ² -(O) _k3 -、CW ¹ ＝CH-CO-(O) _k3 -、CW ¹ ＝CH-CO-NH-、CH ₂ ＝CW ¹ -CO-NH-、

CH ₃ -CH＝CH-O-、(CH ₂ ＝CH) ₂ CH-OCO-、(CH ₂ ＝CH-CH ₂ ) ₂ CH-OCO-、

(CH ₂ ＝CH) ₂ CH-O-、(CH ₂ ＝CH-CH ₂ ) ₂ N-、(CH ₂ ＝CH-CH ₂ ) ₂ N-CO-、HO-CW ² W ³ -、HS-CW ² W ³ -、HW ² N-、HO-CW ² W ³ -NH-、CH ₂ ＝CW ¹ -CO-NH-、CH ₂ ＝CH-(COO) _k1 -Phe-(O) _k2 -、CH ₂ ＝CH-(CO) _k1 -Phe-(O) _k2 -, phe-ch=ch-, HOOC-, OCN-, and W ⁴ W ⁵ W ⁶ Si-, wherein W ¹ Representation H, F, cl, CN, CF ₃ Phenyl or alkyl having 1 to 5C atoms, in particular H, F, cl or CH ₃ ，W ² And W is ³ Each independently of the others represents H or an alkyl radical having 1 to 5C atoms, in particular H, methyl, ethyl or n-propyl, W ⁴ 、W ⁵ And W is ⁶ Each independently of the others represents Cl, oxaalkyl having 1 to 5C atoms or oxacarbonylalkyl, W ⁷ And W is ⁸ Each independently of the others represents H, cl or alkyl having 1 to 5C atoms, phe represents 1, 4-phenylene, which is optionally substituted by one or more groups L other than P-SP-, k as defined above ₁ 、k ₂ And k ₃ Each independently of the others represents 0 or 1, k ₃ Preferably 1, and k ₄ And represents an integer of 1 to 10.

Very preferred groups P are selected from the group consisting of: CH (CH) ₂ ＝CW ¹ -CO-O-、CH ₂ ＝CW ¹ -CO-、 CH ₂ ＝CW ² -O-、CH ₂ ＝CW ² -、CW ¹ ＝CH-CO-(O) _k3 -、CW ¹ ＝CH-CO-NH-、CH ₂ ＝CW ¹ -CO-NH-、(CH ₂ ＝CH) ₂ CH-OCO-、(CH ₂ ＝CH-CH ₂ ) ₂ CH-OCO-、(CH ₂ ＝CH) ₂ CH-O-、(CH ₂ ＝CH-CH ₂ ) ₂ N-、(CH ₂ ＝CH-CH ₂ ) ₂ N-CO-、CH ₂ ＝CW ¹ -CO-NH-、CH ₂ ＝CH-(COO) _k1 -Phe-(O) _k2 -、CH ₂ ＝CH-(CO) _k1 -Phe-(O) _k2 -, phe-ch=ch-and W ⁴ W ⁵ W ⁶ Si-, wherein W ¹ Representation H, F, cl, CN, CF ₃ Phenyl or alkyl having 1 to 5C atoms, in particular H, F, cl or CH ₃ ，W ² And W is ³ Each independently of the others represents H or an alkyl radical having 1 to 5C atoms, in particular H, methyl, ethyl or n-propyl, W ⁴ 、W ⁵ And W is ⁶ Each independently of the others represents Cl, oxaalkyl or oxacarbonylalkyl having 1 to 5C atoms, W ⁷ And W is ⁸ Each independently of the others represents H, cl or alkyl having 1 to 5C atoms, phe represents 1, 4-phenylene, k ₁ 、k ₂ And k ₃ Each independently of the others represents 0 or 1, k ₃ Preferably represents 1, and k ₄ Represents an integer of 1 to 10.

Very preferred groups P are selected from the group consisting of: CH (CH) ₂ ＝CW ¹ -CO-O-, in particular CH ₂ ＝CH-CO-O-、CH ₂ ＝C(CH ₃ ) -CO-O-and CH ₂ =cf-CO-O-, also CH ₂ ＝CH-O-、(CH ₂ ＝CH) ₂ CH-O-CO-、(CH ₂ ＝CH) ₂ CH-O-、

Other particularly preferred polymerizable groups P are selected from ethyleneoxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetane and epoxy groups, most preferably from acrylate and methacrylate groups.

If the spacer group Sp is different from a single bond, it is preferably of the formula Sp "-X" such that the individual groups P-Sp-correspond to the formula R-Sp "-X" -, where

Sp' represents a linear or branched alkylene group having 1 to 20, preferably 1 to 12C atoms, which is optionallyIs mono-or polysubstituted by F, cl, br, I or CN, and wherein, in addition, one or more non-adjacent CH(s) ₂ The radicals are each, independently of one another, each independently of one another, formed by-O-; -S-, -NH-, -N (R) ⁰ )-、-Si(R ⁰ R ⁰⁰ )-、-CO-、-CO-O-、-O-CO-、-O-CO-O-、-S-CO-、-CO-S-、-N(R ⁰⁰ )-CO-O-、-O-CO-N(R ⁰ )-、-N(R ⁰ )-CO-N(R ⁰⁰ ) -, -CH=CH-or-C≡C-is replaced in such a way that O and/or S atoms are not directly attached to each other,

x' represents-O-, -S-, -CO-O-, -O-CO-O-, -CO-N (R) ⁰ )-、-N(R ⁰ )-CO-、-N(R ⁰ )-CO-N(R ⁰⁰ )-、-OCH ₂ -、-CH ₂ O-、-SCH ₂ -、-CH ₂ S-、-CF ₂ O-、-OCF ₂ -、-CF ₂ S-、-SCF ₂ -、-CF ₂ CH ₂ -、-CH ₂ CF ₂ -、-CF ₂ CF ₂ -、-CH＝N-、-N＝CH-、-N＝N-、-CH＝CR ⁰ -、-CY ² ＝CY ³ -, -C.ident.C-, -CH=CH-CO-O-; O-CO-ch=ch-, or a single bond,

R ⁰ and R is ⁰⁰ Each independently of the others represents H or an alkyl group having 1 to 20C atoms, and

Y ² and Y ³ Each independently of the other represents H, F, cl or CN.

X' is preferably-O-, -S-; -CO-, -COO-, -OCO-, -O-COO-, -CO-NR ⁰ -、-NR ⁰ -CO-、-NR ⁰ -CO-NR ⁰⁰ -or a single bond.

Typical spacer groups Sp and-Sp "-X" -are, for example- (CH) ₂ ) _p1 -、-(CH ₂ ) _p1 -O-、-(CH ₂ ) _p1 -O-CO-、-(CH ₂ ) _p1 -CO-O-、-(CH ₂ ) _p1 -O-CO-O-、-(CH ₂ CH ₂ O) _q1 -CH ₂ CH ₂ -、-CH ₂ CH ₂ -S-CH ₂ CH ₂ -、-CH ₂ CH ₂ -NH-CH ₂ CH ₂ -or- (SiR) ⁰ R ⁰⁰ -O) _p1 -, where p1 is an integer from 1 to 12, q1 is an integer from 1 to 3, and R ⁰ And R is ⁰⁰ Having the meaning indicated above.

Particularly preferred groups Sp and-Sp "-X" -are- (CH) ₂ ) _p1 -、-(CH ₂ ) _p1 -O-、-(CH ₂ ) _p1 -O-CO-、-(CH ₂ ) _p1 -CO-O-、-(CH ₂ ) _p1 -O-CO-O-, wherein p1 and q1 have the meanings indicated above.

Particularly preferred groups Sp' are in each case straight-chain ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, octadecylene, ethyleneoxy ethylene, methyleneoxy butylene, ethylenethio ethylene, ethylene-N-methylimino-ethylene, 1-methylalkylene, ethylene, propylene and butylene.

In a preferred embodiment of the invention, the compounds of formula P and its subformulae contain a spacer group Sp substituted with one or more polymerizable groups P, so that the group Sp-P corresponds to Sp (P) _s S is not less than 2 (branched polymerizable group).

Preferred compounds of the formula P according to this preferred embodiment are those in which s is 2, i.e.contain the group Sp (P) ₂ Is a compound of (a). Very preferred compounds of formula P according to this preferred embodiment contain a group selected from the following formulae:

-X-alkyl-CHPP S1

-X-alkyl-CH((CH ₂ ) _aa P)((CH ₂ ) _bb P) S2

-X-N((CH ₂ ) _aa P)((CH ₂ ) _bb P) S3

-X-alkyl-CHP-CH ₂ -CH ₂ P S4

-X-alkyl-C(CH ₂ P)(CH ₂ P)-C _aa H _2aa+1 S5

-X-alkyl-CHP-CH ₂ P S6

-X-alkyl-CPP-C _aa H _2aa+1 S7

-X-alkyl-CHPCHP-C _aa H _2aa+1 S8

Wherein P is as defined in formula P,

alkyl represents a single bond or a straight-chain or branched alkylene radical having 1 to 12C atoms which is unsubstituted or monosubstituted or polysubstituted by F, cl or CN and in which one or more non-adjacent CH' s ₂ The radicals can each be, independently of one another, bound via-C (R) ⁰ )＝C(R ⁰ )-、-C≡C-、-N(R ⁰ ) -, -O-, -S-; -CO-, -CO-O-, -O-CO-, -O-CO-O-substitution, wherein R is ⁰ With the meaning indicated above,

aa and bb each independently of one another represent 0, 1, 2, 3, 4, 5 or 6,

x has one of the meanings indicated for X ", and is preferably O, CO, SO ₂ O-CO-, CO-O, or a single bond.

Preferred spacer groups Sp (P) ₂ Selected from formulas S1, S2 and S3.

Very preferred spacer groups Sp (P) ₂ Selected from the following subformulae:

-CHPP S1a

-O-CHPP S1b

-CH ₂ -CHPP S1c

-OCH ₂ -CHPP S1d

-CH(CH ₂ -P)(CH ₂ -P) S2a

-OCH(CH ₂ -P)(CH ₂ -P) S2b

-CH ₂ -CH(CH ₂ -P)(CH ₂ -P) S2c

-OCH ₂ -CH(CH ₂ -P)(CH ₂ -P) S2d

-CO-NH((CH ₂ ) ₂ P)((CH ₂ ) ₂ P) S3a

in the compounds of formula P and its subformulae as described above and below, P is preferably selected from the group consisting of: vinyloxy, acrylate, methacrylate, fluoroacrylate, chloroacrylate, oxetane and epoxide, most preferably selected from the group consisting of acrylate and methacrylate.

More preferred are compounds of formula P and its subformulae as described hereinabove and hereinbelow, wherein all polymerizable groups P present in the compound have the same meaning and very preferably represent acrylate or methacrylate, most preferably methacrylate.

In the compounds of formula P and its subformulae as described above and below, R preferably represents P-Sp-.

More preferred are compounds of formula P and its subformulae as described hereinabove and hereinbelow wherein Sp represents a single bond or- (CH) ₂ ) _p1 -、-O-(CH ₂ ) _p1 -、-O-CO-(CH ₂ ) _p1 or-CO-O- (CH) ₂ ) _p1 Wherein p1 is 2, 3, 4, 5 or 6, and if Sp is-O- (CH) ₂ ) _p1 -、-O-CO-(CH ₂ ) _p1 or-CO-O- (CH) ₂ ) _p1 The O-atom or the CO-group is attached to the benzene ring, respectively.

More preferred are compounds of formula P and its subformulae as described hereinabove and hereinbelow, wherein at least one group Sp is a single bond.

More preferred are compounds of formula P and its subformulae as described hereinabove and hereinbelow, wherein at least one group Sp is different from a single bond, and is preferably selected from- (CH) ₂ ) _p1 -、-O-(CH ₂ ) _p1 -、-O-CO-(CH ₂ ) _p1 or-CO-O- (CH) ₂ ) _p1 Wherein p1 is 2, 3, 4, 5 or 6, and if Sp is-O- (CH) ₂ ) _p1 -、-O-CO-(CH ₂ ) _p1 or-CO-O- (CH) ₂ ) _p1 The O-atom or the CO-group is attached to the benzene ring, respectively.

Very preferred radicals-A in formula P ¹ -(Z-A ² ) _z -selected from the following formulae

Wherein at least one benzene ring is substituted with at least one group L and the benzene ring is optionally further substituted with one or more groups L or P-Sp-.

Preferred compounds of formula P and sub-formulae thereof are selected from the following preferred embodiments, including any combination thereof:

all groups P in the compounds have the same meaning,

--A ¹ -(Z-A ² ) _z Selected from the formulae A1, A2 and A5,

the compound contains exactly two polymerizable groups (represented by the group P),

the compound contains exactly three polymerizable groups (represented by the group P),

p is selected from the group consisting of acrylates, methacrylates and oxetanes, very preferably acrylates or methacrylates,

p is a methacrylate ester of a methacrylic acid,

all the groups Sp are single bonds,

at least one of the groups Sp being a single bond and at least one of the groups Sp being different from a single bond,

sp is- (CH) when different from single bond ₂ ) _p2 -、-(CH ₂ ) _p2 -O-、-(CH ₂ ) _p2 -CO-O-、-(CH ₂ ) _p2 O-CO-wherein p2 is 2, 3, 4, 5 or 6, the O atom or the CO-group being respectively attached to a benzene ring,

sp is a single bond or represents- (CH) ₂ ) _p2 -、-(CH ₂ ) _p2 -O-、-(CH ₂ ) _p2 -CO-O-、-(CH ₂ ) _p2 O-CO-wherein p2 is 2, 3, 4, 5 or 6, the O atom or the CO-group being respectively attached to a benzene ring,

-R represents P-Sp-,

r does not represent or contains a polymerizable group,

r does not represent or contains a polymerizable group and represents a linear, branched or cyclic alkyl radical having 1 to 25C atoms, in which one or more non-adjacent CH ₂ The radicals optionally being interrupted by-O-, -S-, -CO-, -CO-O-, -O-CO-, O-CO-O-is replaced in such a way that O and/or S atoms are not directly connected to one another, and wherein one or more H atoms are each Optionally via F, cl or L ^a Instead of this, the first and second heat exchangers,

l or L' represents F, cl or CN,

-L is F.

Suitable and preferred compounds of formula P are selected from the following formulae:

/>

wherein the individual radicals have the following meanings:

P ¹ 、P ² and P ³ Each independently of the other represents an acrylate group or a methacrylate group,

Sp ¹ 、Sp ² and Sp ³ Each independently of the others represents a single bond or a spacer group (having one of the meanings as described above and below for Sp), particularly preferably represents- (CH) ₂ ) _p1 -、-(CH ₂ ) _p1 -O-、-(CH ₂ ) _p1 -CO-O-、-(CH ₂ ) _p1 -O-CO-or- (CH) ₂ ) _p1 -O-CO-O-, wherein P1 is an integer from 1 to 12, further wherein the group P ¹ -Sp ¹ -、P ² -Sp ² -and P ³ -Sp ³ One or more of them may represent R ^aa Provided that a group P is present ¹ -Sp ¹ -、P ² -Sp ² -and P ³ -Sp ³ At least one of them is different from R ^aa ，

R ^aa Representation H, F, cl, CN or withStraight or branched alkyl of 1 to 25C atoms, wherein one or more other non-adjacent CH ₂ The radicals may also be replaced independently of one another by C (R ⁰ )＝C(R ⁰⁰ )-、-C≡C-、-N(R ⁰ ) -, -O-, -S-, -CO-; -CO-O-, -O-CO-, O-CO-O-is replaced in such a way that the O and/or S atoms are not directly connected to one another, and wherein another one or more H atoms may be replaced by F, cl, CN or P ¹ -Sp ¹ Alternatively, particular preference is given to straight-chain or branched, optionally mono-or polyfluoro alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy having from 1 to 12C atoms, in which alkenyl and alkynyl have at least two C atoms and the branched radical has at least three C atoms,

R ⁰ 、R ⁰⁰ Each independently of the other and on each occurrence identical or different represent H or an alkyl group having 1 to 12C atoms,

R ^y and R is ^z Each independently of the other represent H, F, CH ₃ Or CF (CF) ₃ ,

X ¹ 、X ² And X ³ Each independently of the other represents-CO-O-; -O-CO-or a single bond,

Z ¹ represents-O-, -CO-, -C (R) ^y R ^z ) -or-CF ₂ CF ₂ -,

Z ² And Z ³ Each independently of the other represents-CO-O-, -O-CO-, -CH ₂ O-，-OCH ₂ -，-CF ₂ O-，-OCF ₂ -or- (CH) ₂ ) _n -, where n is 2,3 or 4,

l represents identically or differently for each occurrence F, cl, CN or a straight-chain or branched, optionally mono-or polyfluoro-substituted alkyl, alkoxy, alkenyl, alkynyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy radical having 1 to 12C atoms, preferably F,

l 'and L' each independently of one another represent H, F or Cl,

k represents either 0 or 1 and,

r represents 0, 1, 2,3 or 4,

s represents 0, 1, 2 or 3,

t represents 0, 1 or 2,

x represents 0 or 1.

Particularly preferred are compounds of the formulae P2, P13, P17, P22, P23, P24, P30, P31 and P32.

Further preferred are the three reactive compounds P15 to P30, in particular P17, P18, P19, P22, P23, P24, P25, P26, P30, P31 and P32.

In the compounds of the formulae P1 to P32, the radicals

Preferably->

Wherein L has, identically or differently at each occurrence, one of the meanings given above or below, and is preferably F, cl, CN, NO ₂ ，CH ₃ ，C ₂ H ₅ ，C(CH ₃ ) ₃ ，CH(CH ₃ ) ₂ ，CH ₂ CH(CH ₃ )C ₂ H ₅ ，OCH ₃ ，OC ₂ H ₅ ，COCH ₃ ，COC ₂ H ₅ ，COOCH ₃ ，COOC ₂ H ₅ ，CF ₃ ，OCF ₃ ，OCHF ₂ ，OC ₂ F ₅ Or P-Sp-, very preferably F, cl, CN, CH ₃ ，C ₂ H ₅ ，OCH ₃ ，COCH ₃ ，OCF ₃ Or P-Sp-, more preferably F, cl, CH ₃ ，OCH ₃ ，COCH ₃ Or OCF (optical clear) ₃ In particular F or CH ₃ 。

Very particularly preferred compounds of the formula P are selected from the following Table E, in particular from the formulae RM-1, RM-4, RM-8, RM-17, RM-19, RM-35, RM-37, RM-39, RM-40, RM-41, RM-48, RM-52, RM-54, RM-57, RM-58, RM-64, RM-74, RM-76, RM-88, RM-91, RM-102, RM-103, RM-109, RM-116, RM-117, RM-120, RM-121, RM-122, RM-139, RM-140, RM-142, RM-143, RM-145, RM-146, RM-147, RM-149, RM-156 to RM-163, RM-169, RM-170 and RM-171 to RM-183.

In order to produce a PSA display, the polymerizable compound contained in the LC medium is polymerized or crosslinked (if one compound contains two or more polymerizable groups) by in situ polymerization in the LC medium (between the substrates of the LC display), optionally while applying a voltage to the electrodes.

The structure of the PSA display according to the invention corresponds to the usual geometry of PSA displays, as described in the prior art cited at the outset. The geometry without protrusions is preferred, wherein in addition, in particular, the electrodes on the color filter side are unstructured and only the electrodes on the TFT side have slots (slots). A particularly suitable and preferred electrode structure for PS-VA displays is described, for example, in US 2006/0066793 A1.

The preferred PSA-type LC display of the present invention comprises:

a first substrate comprising pixel electrodes defining pixel areas, which pixel electrodes are connected to switching elements arranged in each pixel area and optionally comprise a micro slit pattern, and optionally a first alignment layer arranged on the pixel electrodes,

a second substrate comprising a common electrode layer (which may be arranged on the whole part of the second substrate facing the first substrate), and optionally a second alignment layer,

-an LC layer disposed between the first and second substrates and comprising an LC medium comprising a polymerisable component comprising one or more compounds of formula R and a liquid-crystalline host comprising a compound of formula R as described above and below, wherein the polymerisable component may also be polymerised.

The first and/or second alignment layers control the alignment direction of LC molecules of the LC layer. For example, in a PS-VA display, the alignment layer is selected to impart homeotropic (or homeotropic) alignment (i.e., normal to the surface) or tilt alignment to the LC molecules. Such an alignment layer may for example comprise polyimide, which may also be rubbed or may be prepared by a photoalignment method.

The LC layer with LC medium may be deposited between the substrates of the display by methods conventionally used by display manufacturers, such as the so-called drop fill (ODF) method. The polymerisable component of the LC medium is then polymerised, for example by UV photopolymerization. The polymerization may be carried out in one step or in two or more steps.

PSA displays may include other elements such as color filters, black matrices, passivation layers, optical retardation layers, transistor elements for single pixel addressing, etc., all of which are well known to those skilled in the art and may be used without the inventive skill.

One skilled in the art can design the electrode structure depending on the individual display type. For example, for PS-VA displays, the multi-domain orientation of LC molecules may be induced by providing electrodes with slits and/or protrusions (bumps) or projections in order to create two, four or more differently tilted alignment directions.

After polymerization, the polymerizable compounds form crosslinked polymers, which lead to a certain pretilt of the LC molecules in the LC medium. Without wishing to be bound by a particular theory, it is believed that at least a portion of the crosslinked polymer formed by the polymerizable compound will separate or precipitate out of the LC medium and form a polymer layer on the substrate or electrode, or on an alignment layer provided thereon. Microscopic measurement data (such as SEM and AFM) have demonstrated that at least a portion of the formed polymer accumulates at the LC/substrate interface.

The polymerization may be carried out in one step. It is also possible to first carry out the polymerization in a first step (optionally with simultaneous application of voltage) in order to produce a pretilt angle and then to polymerize or crosslink the compounds which have not reacted in the first step in a second polymerization step in which no voltage is applied ("final cure").

Suitable and preferred polymerization methods are, for example, thermal or photopolymerization, preferably photopolymerization, in particular UV-induced photopolymerization, which can be achieved by exposing the polymerizable compound to UV radiation.

Optionally, one or more polymerization initiators are added to the LC medium. Suitable conditions for polymerization and suitable classes of initiatorsThe types and amounts are known to the person skilled in the art and are described in the literature. Suitable for free-radical polymerization are, for example, commercially available photoinitiatorsOr (b)(Ciba AG). If a polymerization initiator is used, the proportion thereof is preferably from 0.001 to 5% by weight, particularly preferably from 0.001 to 1% by weight.

The polymerizable compounds according to the invention are also suitable for polymerization without initiator, which is accompanied by considerable advantages, such as low material costs and in particular less contamination of the LC medium by possible residual amounts of initiator or degradation products thereof. The polymerization can also be carried out without addition of initiator. In a preferred embodiment, the LC medium thus contains no polymerization initiator.

The LC medium may also contain one or more stabilizers in order to prevent undesired spontaneous polymerization of the RM, for example during storage or transport. Suitable types and amounts of stabilizers are known to the person skilled in the art and are described in the literature. Particularly suitable are, for example, those commercially available fromstabilizers of series (Ciba AG), e.g.1076. If stabilizers are used, their proportion is preferably from 10 to 500,000ppm, particularly preferably from 50 to 50,000ppm, based on the total amount of RM or polymerizable components (component P).

The polymerizable compounds of formula P do in particular show good UV absorption and are therefore particularly suitable for use in a process for the production of PSA displays comprising one or more of the following features:

exposing the polymerizable medium to UV light in a 2-step process in a display, the process comprising a first UV exposure step ("UV-1 step") to produce a tilt angle, and a second UV exposure step ("UV-2 step") to complete the polymerization,

in the display the polymerizable medium is exposed to UV light generated by an energy saving UV lamp (also called "green UV lamp"). These lamps are characterized by a relatively low intensity in their absorption spectrum of 300-380nm (1/100-1/10 of conventional UV1 lamps) and are preferably used in the UV2 step, but are optionally also used in the UV1 step when high intensities are to be avoided for the process.

The polymerizable medium is exposed to UV light generated by a UV lamp in the display, which has a radiation spectrum shifted to longer wavelengths (preferably 340nm or longer) to avoid short UV light exposure in the PS-VA process.

Both low intensity and UV shifted to longer wavelengths are used to protect the organic layer from damage that may be caused by UV light.

Preferred embodiments of the present invention relate to a method of making a PSA display as described above and below, comprising one or more of the following features:

exposing the polymerizable LC medium to UV light in a 2-step process comprising a first UV exposure step ("UV-1 step") to produce a tilt angle and a second UV exposure step ("UV-2 step") to complete the polymerization,

the polymerizable LC medium was exposed to a UV lamp with 0.5mW/cm ² To 10mW/cm ² Preferably it is used for the UV2 step, and optionally also for the UV1 step,

the polymerizable LC medium is exposed to UV light having a wavelength of 340nm or more, and preferably 400nm or less.

Such a preferred method is performed, for example, by using a desired UV lamp, or by using a bandpass filter and/or a cutoff filter that is substantially transmissive to UV light having the respective desired wavelength and substantially blocking UV light having the respective undesired wavelength. For example, when radiation of UV light having a wavelength λ of 300-400nm is desired, UV exposure may be performed using a broadband pass filter substantially transmissive for wavelengths of 300nm < λ <400 nm. When radiation of UV light having a wavelength lambda greater than 340nm is desired, UV exposure may be performed using a cut-off filter that is substantially transmissive to wavelengths lambda >340 nm.

By "substantially transmissive" is meant that the filter transmits a substantial portion, preferably at least 50%, of the intensity of incident light of the desired wavelength. By "substantially blocked" is meant that the filter does not transmit a substantial portion, preferably at least 50%, of the intensity of incident light of the undesired wavelength. "desired (undesired) wavelength", for example, means a wavelength within (outside) a given lambda range in the case of a band-pass filter, and a wavelength higher (lower) than a given lambda value in the case of a cut-off filter.

This preferred method makes it possible to manufacture displays by using longer UV wavelengths, thereby reducing or even avoiding the deleterious and damaging effects of short UV light components.

The UV radiation energy is typically 6 to 100J, depending on the production process conditions.

Preferably, the LC medium according to the invention essentially consists of a polymerizable component P) comprising one or more polymerizable compounds of formula P and LC host mixture as described above and below, and an optically active component comprising one or more chiral dopants. However, the LC medium may additionally comprise one or more other components or additives, preferably selected from the list including, but not limited to: comonomers, polymerization initiators, inhibitors, stabilizers, surfactants, wetting agents, lubricants, dispersants, hydrophobing agents, binders, flow improvers, defoamers, deaerators, diluents, reactive diluents, auxiliaries, colorants, dyes, pigments and nanoparticles.

Particularly preferred are LC media comprising one, two or three polymerizable compounds of formula P.

Preferably the proportion of the compound of formula P in the LC medium is >0 to <5%, very preferably >0 to <1%, most preferably 0.01 to 0.5%.

In a preferred embodiment, the medium according to the invention preferably comprises one or more compounds of the formula S in a total concentration in the range from 10ppm to 2000ppm, more preferably from 100ppm to 1000ppm, still more preferably from 150ppm to 500ppm, very preferably from 200ppm to 400ppm and in particular from 250 to 300ppm.

In a further preferred embodiment, the medium according to the invention preferably comprises one or more compounds of the formula S in a total concentration in the range from 1000ppm to 5000ppm, more preferably from more than 1000ppm to 5000ppm, still more preferably from 1200ppm to 4500ppm, very preferably from 2000ppm to 4000ppm and in particular from 2500 to 3500ppm.

The medium according to the invention preferably has a negative dielectric anisotropy.

The medium according to the invention comprises one or more compounds of the formula I in a total concentration in the range >0% to 20%, preferably 1% to 15%, more preferably 2% to 13%, very preferably 3% to 12%.

The medium according to the invention preferably comprises

-one or more compounds selected from the group of compounds of formulae IIA, IIB, IIC and IID in a total concentration ranging from 9% to 70%, more preferably from 10% to 65% and very preferably from 11% to 64%, in particular from 28% to 42% or from 9% to 20% or from 50% to 64%;

And/or

-one or more compounds selected from the group of compounds of formulae IIA, IIB, IIC and IID and, in addition, one or more compounds of formula III, in a total concentration ranging from 20% to 60%, more preferably from 25% to 55% and very preferably from 27% to 52%;

and/or

-one or more compounds of formula IIA, preferably of formula IIA-10, in a total concentration ranging from 1% to 30%, more preferably from 2% to 28% and very preferably from 3% to 27%;

or (b)

-one or more compounds of formula IIA, preferably of formula IIA-10, preferably in a total concentration ranging from 1% to 10%, more preferably from 2% to 9% and very preferably from 3% to 8%;

or less than 2%, preferably from 0 to 1%,

and/or

-one or more compounds of formula IIB, preferably of formula IIB-2 and/or IIB-10, in a total concentration ranging from 1% to 30%, more preferably from 2% to 28% and very preferably from 3% to 25%, in particular from 10% or 15% to 25%;

and/or

-one or more compounds of formula IIC, preferably in a total concentration ranging from 1% to 20%, more preferably from 2% to 18% and very preferably from 3% to 16%, in particular from 4% to 15%;

and/or

-one or more compounds of formula IID and preferably formula IID-4, preferably in a total concentration ranging from 5% to 25%, more preferably from 7% to 20% and very preferably from 8% to 18%;

And/or

-one or more compounds of formulae IIB and IID in a total concentration ranging from 18% to 45%, more preferably from 22% to 38% and very preferably from 25% to 35%;

and/or

-one or more compounds of formulae IIB and IIC in a total concentration ranging from 5% to 28%, more preferably from 8% to 23% and very preferably from 10% to 20%;

and/or

-one or more compounds of formula III, preferably formula III-2, more preferably formula III-2-6, preferably in a total concentration ranging from 3% to 20%, more preferably from 5% to 17% and very preferably from 6% to 15%;

and/or

-one or more compounds of formula III-2, more preferably formula III-2-6, and one or more compounds of formula III-3 in a total concentration ranging from 10% to 30%, more preferably from 15% to 27% and very preferably from 18% to 24%;

and/or

-one or more compounds of formula IV in a total concentration ranging from 20% to 65%, more preferably from 28% to 58%, still more preferably from 30% to 55% and very preferably from 32% to 50%, in particular from 35% to 48%;

and/or

-one or more compounds of formula IV and one or more compounds of formula Iva and/or IVb, preferably in a total concentration ranging from 28% to 70%, more preferably from 30% to 65%, still more preferably from 35% to 62% and very preferably from 40% to 60%, in particular from 42% to 58%;

And/or

-one or more compounds of formula IV-1, preferably in a total concentration ranging from 1% to 15%, more preferably from 2% to 12%, still more preferably from 3% to 10% and very preferably from 3% to 8%;

and/or

-one or more compounds of formula IV-2, preferably in a total concentration ranging from 0.2% to 5%, more preferably from 0.5% to 3%, still more preferably from 1% to 2%;

and/or

-one or more compounds of formula IV-3, preferably selected from formulae IV-3-1 and IV-3-2, very preferably formula IV-3-1a and/or IV-3-1c and/or IV-3-2a and/or IV-3-2b, preferably in a total concentration range of 25% to 55%, more preferably 28% to 50%, still more preferably 32% to 47% and very preferably 38% to 45%;

and/or

-one or more compounds of formula IV-3-2a and/or IV-3-2b, preferably in a total concentration ranging from 16% to 32%, more preferably from 18% to 30%, still more preferably from 20% to 28% and very preferably from 22% to 26%;

and/or

-one or more compounds of formula IVb, preferably IVb-2-3, in a total concentration ranging from 1% to 20%, more preferably from 2% to 18%, still more preferably from 4% to 16% and very preferably from 5% to 15%;

and/or

-one or more compounds of formula V in a total concentration ranging from 3% to 15%, more preferably from 4% to 14%, still more preferably from 5% to 13% and very preferably from 6% to 12%;

And/or

One or more compounds of formula IIA-Y, preferably formula IIA-Y6, have a total concentration in the range of 0.5% to 10%, more preferably 1% to 8%, and very preferably 2% to 5%.

In a very preferred embodiment, the medium according to the invention comprises

-one or more compounds of formula I-3a, and

one or more compounds of the formula IIB, preferably of the formula IIB-2 and/or IIB-10, in a total concentration in the range from 12% to 32%, more preferably from 14% to 30% and very preferably from 15% to 27%,

and

-one or more compounds of formula IID, preferably formula IID-4, preferably in a total concentration ranging from 5% to 20%, more preferably from 7% to 18% and very preferably from 8% to 16%;

and

-one, two or three compounds of formula III-2-6, in a total concentration ranging from 3% to 20%, more preferably from 5% to 17% and very preferably from 7% to 15%;

and

-one or more compounds of formula IV-1 in a total concentration ranging from 1% to 15%, more preferably from 2% to 12%, still more preferably from 3% to 10% and very preferably from 3% to 8%;

and

-one or more compounds of formula IV-3-1a and/or IV-3-1b in a total concentration ranging from 12% to 25%, more preferably from 14% to 22%, and very preferably from 16% to 20%;

and

-one or more compounds of formula IV-3-2a and/or IV-3-2b in a total concentration ranging from 16% to 32%, more preferably from 18% to 30%, still more preferably from 20% to 28% and very preferably from 22% to 26%.

In another very preferred embodiment, the medium according to the invention comprises

-one or more compounds of formula I-3b, and

one or more compounds of the formula IIB, preferably of the formula IIB-2 and/or IIB-10, in a total concentration in the range from 6% to 32%, more preferably from 9% to 30% and very preferably from 10% to 22%,

and

-one or more compounds of formula IID, preferably formula IID-4, preferably in a total concentration ranging from 5% to 25%, more preferably from 7% to 22% and very preferably from 8% to 20%;

and

-one or more compounds of formula IV-1 in a total concentration ranging from 1% to 20%, more preferably from 2% to 18%, still more preferably from 3% to 15% and very preferably from 4% to 13%;

and

-one or more compounds of formula IV-3-1a and/or IV-3-1b and/or IV-3-1c in a total concentration ranging from 12% to 40%, more preferably from 14% to 35%, and very preferably from 16% to 30%;

And

-one or more compounds of formula IV-3-2a and/or IV-3-2b in a total concentration ranging from 3% to 35%, more preferably from 5% to 30%, still more preferably from 6% to 26% and very preferably from 7% to 24%.

As liquid-crystalline media according to the invention, it is advantageous to have nematic phases of from.ltoreq.20℃to.gtoreq.70℃and particularly preferably from.ltoreq.30℃to.gtoreq.72℃and very particularly preferably from.ltoreq.40℃to.gtoreq.74℃.

In a first preferred embodiment, the medium according to the invention has a clearing temperature of 70 ℃ or more, preferably 72 ℃ or more, more preferably 73 ℃ or more and in particular 74 ℃ or more.

The expression "having a nematic phase" here means on the one hand that no smectic phase and no crystallization are observed at the respective temperatures at low temperatures and on the other hand that the heating from the nematic phase does not yet clear (phase transition to isotropic phase). The low temperature study was performed in a flow viscometer at the corresponding temperature and tested by storage in a test box having a layer thickness corresponding to the electro-optic application for at least 100 hours. If the storage stability in the corresponding test cartridge is 1000 hours or more at a temperature of-20 ℃, the medium is said to be stable at that temperature. The response times were 500 hours and 250 hours at temperatures of-30℃and-40℃respectively. At elevated temperature, the clearing point is measured in a capillary tube by conventional methods.

The liquid-crystalline mixture preferably has a thickness of at most 30mm at 20 DEG C ² ·s ^-1 Is a flow viscosity v ₂₀ 。

The liquid-crystalline mixtures according to the invention are nematic, preferably at a temperature of-20℃or less, preferably-30℃or less, very preferably-40℃or less.

In a preferred embodiment of the invention, the medium has a birefringence of 0.105 or higher.

In a preferred embodiment of the invention, the medium has a birefringence in the range of 0.1050 to 0.155, more preferably 0.1055 to 0.150, very preferably 0.110 to 0.145 and in particular 0.115 to 0.143.

In a preferred embodiment of the invention, the medium has a birefringence in the range of from 0.125 to 0.155, more preferably from 0.130 to 0.150, very preferably from 0.135 to 0.145 and in particular from 0.137 to 0.143.

In a preferred embodiment of the invention, the medium has a birefringence in the range of 0.100 to 0.113, preferably 0.105 to 0.109.

In a preferred embodiment of the invention, the medium has a birefringence in the range of 0.115 to 0128, preferably 0.118 to 0.122.

In a preferred embodiment, the liquid-crystalline mixtures according to the invention have a dielectric anisotropy Δεof from-1.8 to-5.0, preferably from-1.9 to-4.8, in particular from-2.0 to-3.9.

In a preferred embodiment, the liquid-crystalline mixtures according to the invention have a dielectric anisotropy Δεof from-2.0 to-3.8, preferably from-2.3 to-3.4, in particular from-2.8 to-3.2.

Rotational viscosity gamma at 20 DEG C ₁ The preferred range is from 60 to 120mPas, more preferably from 70 to 110 mPas.

Spring constant K ₁ The preferred range is from 17.0 to 25.0, more preferably from 18.0 to 24.0, especially from 19.0 to 22.0.

Spring constant K ₃ The preferred range is 16.0 to 24.0, more preferably 17.0 to 23.0, especially 18.0 to 21.0.

Furthermore, the liquid-crystalline medium according to the invention has a high voltage retention value in the liquid-crystalline cell.

In general, liquid crystal media with low addressing voltages or threshold voltages exhibit lower voltage retention than those with higher addressing voltages or threshold voltages, and vice versa.

For the purposes of the present invention, the term "dielectrically positive compounds" means compounds having a Δε >1.5, the term "dielectrically neutral compounds" means those having a Δε of-1.5.ltoreq.Δε.ltoreq.1.5 and the term "dielectrically negative compounds" means those having a Δε < -1.5. Here, the dielectric anisotropy of the compounds is determined by dissolving 10% of the compounds in the liquid-crystalline host in at least one test cell and measuring the capacitance of the resulting mixture, the test cell in each case having a layer thickness of 20 μm and having homeotropic and faceted surface alignment at 1 kHz. The measurement voltage is typically 0.5V-1.0V, but always below the capacitance threshold of the respective liquid crystal mixture under investigation.

All temperature values according to the invention are expressed in degrees celsius.

The mixtures according to the invention are suitable for all VA-TFT applications, such as, for example, VAN, MVA, (S) -PVA, ASV, PSA (Polymer-sustained VA,) and PS-VA (Polymer stabilized VA). It is furthermore suitable for IPS (in-plane switching mode) and FFS (fringe field switching mode) applications with negative Δ∈, in particular UB-FFS.

It will be apparent to those skilled in the art that VA, IPS or FFS mixtures according to the invention may also comprise compounds in which, for example, H, N, O, cl and F are replaced by the corresponding isotopes.

The compounds according to the invention can be synthesized by known methods (e.g. in standard works, such as Houben-Weyl, methoden der Organischen Chemie [ Methods of Organic Chemistry ], georg-Thieme-Verlag, stuttgart) or analogously to those described in the literature under reaction conditions known and suitable for the reaction. Variants known per se can also be used here, but are not mentioned here. In particular, they may be prepared as described in or analogous to the following schemes. Other methods of preparing the compounds of the present invention can be obtained from the examples.

Other mesogenic compounds not explicitly mentioned above may also optionally and advantageously be used in the medium according to the invention. Such compounds are known to those skilled in the art.

Detailed Description

For the present invention and in the following examples, the structures of the liquid crystal compounds are indicated by abbreviations, which are converted into chemical formulas according to tables a to C below. All radicals C _m H _2m+1 、C _n H _2n+1 And C _l H _2l+1 Or C _m H _2m-1 、C _n H _2n-1 And C _l H _2l-1 Is a linear alkyl group or an alkylene group, each having n, m and l C atoms. Preferably, n, m and l are each independently 1,2,3,4,5,6 or 7. Table A shows the codes for the ring elements of the compound core, table B lists the bridging units, and Table C lists the symbolic meanings of the left-hand and right-hand end groups of the molecule. The abbreviation consists of a code of ring elements with optional linking groups, followed by a first hyphen and a left-hand end code, and a second hyphen and a right-hand end code. Table D shows exemplary structures of compounds and their respective abbreviations.

Table a: ring element

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Table B: bridging unit

Table C: end group

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Where n and m are each integers, and three points ".." is a placeholder for other abbreviations from the table.

In addition to the compounds of formulae I, IIA, IIB, IIC and/or IID, IVa, IVb and V, the mixtures of the present invention optionally comprise one or more of the following compounds.

The following abbreviations are used:

(n, m, k and l are each independently of the other integers, preferably from 1 to 9, preferably from 1 to 7,k and l may also be 0 and preferably from 0 to 4, more preferably 0 or 2 and most preferably 2, n is preferably 1,2,3,4 or 5, in combination "-nO-" it is preferably 1,2,3 or 4, preferably 2 or 4, m is preferably 1,2,3,4 or 5, in combination "-Om" it is preferably 1,2,3 or 4, more preferably 2 or 4, combination "-lVm" is preferably "2V 1").

Table D

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Table E

Table E shows illustrative reactive mesogenic compounds that can be used in LC media according to the invention

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In a preferred embodiment, the mixture according to the invention comprises one or more polymerizable compounds, preferably selected from the group of polymerizable compounds of the formulae RM-1 to RM-182. Of these, compounds RM-1, RM-4, RM-8, RM-17, RM-19, RM-35, RM-37, RM-39, RM-40, RM-41, RM-48, RM-52, RM-54, RM-57, RM-58, RM-64, RM-74, RM-76, RM-88, RM-91, RM-102, RM-103, RM-109, RM-116, RM-117, RM-120, RM-121, RM-122, RM-139, RM-140, RM-142, RM-143, RM-145, RM-146, RM-147, RM-149, RM-156 to RM-163, RM-169, RM-170, and RM-171 to RM-183 are particularly preferred.

Examples

The invention is illustrated in detail by the following non-limiting working examples.

The following abbreviations and symbols are used:

V _o represents the threshold voltage at 20 ℃, the capacitance [ V],

n _e Represents an extraordinary refractive index at 20℃and 589nm,

n _o represents the ordinary refractive index at 20℃and 589nm,

Δn represents optical anisotropy at 20℃and 589nm,

ε _⊥ represents the dielectric constant perpendicular to the director at 20 c and 1kHz,

ε _|| represents the dielectric constant parallel to the director at 20 c and 1kHz,

delta epsilon represents the dielectric anisotropy at 20 deg.c and 1kHz,

cl.p., T (N, I) represents a clear light spot [. Degree.C ],

γ ₁ represents the rotational viscosity [ mPa.s ] at 20 DEG C]，

K ₁ Represents the elastic constant, the "splay" deformation at 20℃pN],

K ₂ Represents the elastic constant, the "distortion" deformation at 20℃pN],

K ₃ Represents the elastic constant, the "bending" deformation at 20℃pN],

Unless explicitly stated otherwise, all concentrations in this application are expressed in weight percent and relate to the corresponding mixture as a whole, including all solid or liquid crystal components, without solvent.

All temperature values indicated in the present application, e.g. melting point T (C, N), transition from smectic phase (S) to nematic phase (N) T (S, N) and clearing point T (N, I) are all referred to in degrees celsius (°c), unless otherwise indicated. M.p. represents melting point, cl.p. =clearing point. Further, c=crystalline, n=nematic, s=smectic and i=isotropic phases. The data between these symbols represents the transition temperature.

Unless otherwise indicated, all physical properties were and have been determined in accordance with "Merck Liquid Crystals, physical Properties of Liquid Crystals", status nov 1997, merck KGaA, germany, and applied to temperatures of 20 ℃, and Δn at 589nm and Δε at 1kHz in each case.

The term "threshold voltage" as used in the present invention relates to the capacitive threshold (V ₀ ) It is also referred to as the Freedericks threshold unless otherwise indicated. In an embodiment, as usual, the optical threshold may also be a relative contrast ratio (V ₁₀ ) Cited, are incorporated herein by reference.

The process of polymerizing the polymerizable compounds in PSA displays as described above and as described below, unless otherwise indicated, is carried out at a temperature at which the LC medium exhibits a liquid crystal phase, preferably a nematic phase, and most preferably at room temperature.

Unless otherwise specified, the methods of preparing the test cartridge and measuring its electro-optic and other properties should be performed using methods described below or similar thereto.

The display for measuring the capacitive threshold voltage consists of two plane-parallel glass outer plates at a distance of 25 μm, each having an electrode layer on the inside and an unwarped polyimide alignment layer on top, which results in a vertical alignment of the liquid crystal molecules.

The display or test cell for measuring the tilt angle consists of two plane-parallel glass outer plates separated by 4 μm, each of which has an electrode layer and a polyimide alignment layer on top on the inside, where the two polyimide layers rub against each other antiparallel and cause vertical edge alignment of the liquid crystal molecules.

The polymerizable compound is applied to the display or meter by irradiating UV light of a defined intensity for a predetermined time while applying a voltage (typically 10V-30V alternating current, 1 kHz) to the displayPolymerization in the test kit. In the examples, unless otherwise indicated, fluorescent lamps and 0 to 20mW/cm were used ² Is polymerized. The intensity was measured using a standard instrument (Ushio Accumulate UV instrument (UV meter) with a center wavelength of 313 nm).

Transmittance (transmission) measurements (from Merck ltd., japan;1 pixel fishbone electrode (ITO, 10x10mm, fishbone angle 47.7 °,3 μm line/3 μm space), 3.2 μm cell gap, AF-glass, tilt 1 °) were performed in a test cartridge with a fishbone electrode layout.

Storage stability (LTS) in bulk (bulk) of the medium according to the invention at a given temperature T _Body ) Measured by visual inspection. 2g of medium of interest are filled into suitably sized closed glass containers (bottles) placed in a refrigerator at a predetermined temperature. The bottles were checked at defined time intervals for the occurrence of smectic phases or crystallization. For each material and each temperature, two bottles were stored. If the appearance of crystalline or smectic phases is observed in at least one of the two respective bottles, the test is terminated and the time of the last check before the appearance of the higher order phase is observed is recorded as the respective storage stability.

Examples of mixtures

Mixture examples M1 to M75 and P1 to P10 have the compositions and physical properties shown in the following table:

mixture example M1

Mixture example M2

Mixture example M3

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In the following table, the key parameters of mixtures M1 to M3 are summarized.

By using the compounds of the formula I in a medium having negative dielectric anisotropy, it has surprisingly been found that an advantageously low rotational viscosity (gamma ₁ ) At the same time at a very low rate gamma ₁ and/K1, which improves the response time of the display.

Mixture example M4

Mixture example M5

Mixture example M6

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Mixture example M7

Mixture example M8

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Mixture example M9

Mixture example M10

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Mixture example M11

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Mixture example M12

Mixture example M13

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Mixture example M14

Mixture example M15

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Mixture example M16

Mixture example M17

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Mixture example M18

Mixture example M19

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Mixture example M20

Mixture example M21

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Mixture example M22

Mixture example M23

Mixture example M24

Mixture example M25

Mixture example M26

Mixture example M27

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Mixture example M28

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Mixture example M29

Mixture example M30

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Mixture example M31

Mixture example M32

Mixture example M33

Examples of mixturesM34

Mixture example M35

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Mixture example M36

Mixture example M37

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Mixture example M38

Mixture example M39

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Mixture example M40

Mixture example M41

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Mixture example M42

The mixture example M42 consists of 99.98% of the mixture example M1 and 0.02% of the compound of the formula ST-12b-1

Mixture example M43

The mixture example M43 consists of 99.985% of the mixture example M1 and 0.015% of the compound of the formula S1-1a

Mixture example M44

The mixture example M44 consists of 99.98% of the mixture example M2 and 0.02% of the compound of the formula S2-1a

Mixture example M45

Mixture example M46

Mixture example M47

Mixture example M48

Mixture example M49

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Mixture example M50

Mixture example M51

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Mixture example M52

Mixture example M53

Mixture example M54

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Mixture example M55

Mixture example M56

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Mixture example M57

Mixture example M58

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Mixture example M59

Mixture example M60

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Mixture example M61

Mixture example M62

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Mixture example M63

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Mixture example M64

Mixture example M65

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Mixture example M66

Mixture example M67

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Mixture example M68

Mixture example M69

Mixture example M70

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Mixture example M71

Mixture example M72

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Mixture example M73

Mixture example M74

Mixture example M75

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Mixture example M76

Mixture example M77

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Mixture example M78

Mixture example M79

Mixture example M80

Mixture example M81

Mixture example M82

Mixture example M83

Mixture example M84

Mixture example M85

Mixture example M86

Mixture example M87

Mixture example M88

Mixture example M89

Mixture example M90

Mixture example M91

Mixture example M92

Polymerizable mixture

The polymerizable mixtures P1 to P9 were prepared from the nematic mixtures given in Table 1 by adding Reactive Mesogens (RM) selected from the group of compounds of the formulae RM-1, RM-17, RM-35, RM-64 and RM-171 in the amounts (% RM) given in Table 1.

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TABLE 1 polymerizable mixture

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Mixture example P10

The polymerizable mixture P10 was composed of 99.434% of mixture example M1, 0.300% of RM-1, 0.200% of RM-145, 0.050% of RM-163, 0.001%1076 and 0.015% of compound ST-3 a-1.

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Claims

1. A liquid crystalline medium comprising

a) One or more compounds of formula I

Wherein the method comprises the steps of

R ¹ And R is ² Identically or differently, represents H, halogen, straight-chain alkyl or alkoxy having 1 to 15C atoms, straight-chain alkenyl or alkenyloxy having 2 to 15C atoms or branched-chain alkyl or alkoxy or alkenyl or alkenyloxy having 3 to 15C atoms, where one or more of these radicals CH ₂ The radicals can each be, independently of one another, substituted -C≡C-，-CF ₂ O-，-OCF ₂ -, -ch=ch-, -O-, -CO-O-, or-O-CO-such that the O atoms are not directly attached to each otherAnd wherein one or more H atoms may be replaced by halogen,

Z ¹ and Z ² Each independently of the other, represents-CF ₂ O-，-OCF ₂ -，-CH ₂ O-,-OCH ₂ -，-CO-O-，-O-CO-，-C ₂ H ₄ -，-C ₂ F ₄ ，-CF ₂ CH ₂ -，-CH ₂ CF ₂ -，-CFHCFH-，-CFHCH ₂ -，-CH ₂ CFH-，-CF ₂ CFH-，-CFHCF ₂ -, -ch=ch-, -cf=ch-, -ch=cf-, -cf=cf-, -c≡c-, or a single bond;

m represents 0,1, 2 or 3; and

n represents 0,1, 2 or 3;

and

Wherein the method comprises the steps of

R ^2A ，R ^2B ，R ^2C And R is ^2D Identically or differently, represents H, straight-chain alkyl or alkoxy having 1 to 15C atoms, straight-chain alkenyl or alkenyloxy having 2 to 15C atoms or branched-chain alkyl or alkoxy or alkenyl or alkenyloxy having 3 to 15C atoms, where one or more of these radicals CH ₂ The radicals can each be, independently of one another, substituted -C≡C-，-CF ₂ O-，-OCF ₂ -, -CH=CH-, surrounded by-O-, CO-O-or-O-CO-is replaced in such a way that the O atoms are not directly connected to each other, and wherein one or more H atoms may be replaced by halogen,

Y represents H, F, cl, CF ₃ ，CHF ₂ Or CH (CH) ₃ ，

p represents a group selected from 0,1 or 2,

q represents 0 or 1, and

v represents an integer of 1 to 6.

2. The liquid-crystalline medium according to claim 1, wherein the total amount of one or more compounds selected from the group of compounds of formulae IIA, IIB, IIC and IID ranges from 9% to 70%.

3. The liquid-crystalline medium according to claim 1, wherein the one or more compounds of the formula I are selected from the group consisting of compounds of the formulae I-1 to I-6

Wherein R is ¹ And R is ² Having the meaning given in claim 1, and r,s and t are independently 0,1,2,3, or 4.

4. A liquid-crystalline medium according to claim 3, wherein the radicals in the formulae I-1 to I-6Representation of

5. The liquid-crystalline medium according to one or more of claims 1 to 4, wherein the medium comprises one or more compounds of the formula III

Wherein the method comprises the steps of

R ³¹ And R is ³² Each independently of the others represents H, alkyl or alkoxy having 1 to 15C atoms, where one or more CH's in these groups ₂ The radicals being each independently of the other-C≡C-，-CF ₂ O-，-OCF ₂ -, -CH=CH-, surrounded by-O-, CO-O-or-O-CO-is replaced in such a way that the O atoms are not directly connected to each other, and wherein one or more H atoms may be replaced by halogen,

A ³¹ each occurrence is independently represented

b) 1, 4-phenylene in which one or two CH groups may be replaced by N, or

n represents a number of 0,1 or 2,

L ³¹ and L ³² Each independently of the other represents F, cl, CF ₃ Or CHF ₂ A kind of electronic device

W represents O or S.

6. A liquid-crystalline medium according to claim 5, wherein W in formula III represents S.

7. The liquid-crystalline medium according to one or more of claims 1 to 6, wherein the medium comprises one or more compounds of the formula IV

Wherein the method comprises the steps of

R ⁴¹ Represents an unsubstituted alkyl group having 1 to 7C atoms or an unsubstituted alkenyl group having 2 to 7C atoms,

R ⁴² represents an unsubstituted alkyl group having 1 to 7C atoms or an unsubstituted alkoxy group having 1 to 6C atoms, or an unsubstituted alkenyl group having 2 to 7C atoms.

8. The liquid-crystalline medium according to one or more of claims 1 to 7, wherein the medium comprises one or more compounds of the formulae IV-3-1 and IV-3-2:

wherein alkyl represents an n-alkyl group having 1 to 7C atoms.

9. The liquid-crystalline medium according to one or more of claims 1 to 8, wherein the medium comprises one or more compounds of the formula V

Wherein the method comprises the steps of

R ⁵¹ ，R ⁵² Represents alkyl having 1 to 7C atoms, alkoxy having 1 to 7C atoms, or alkoxyalkyl, alkenyl or alkenyloxy having 2 to 7C atoms, Identically or differently, denote

Z ⁵¹ And Z ⁵² Identically or differently, represent-CH ₂ -CH ₂ -，-CH ₂ -O-, -ch=ch-, -c≡c-, -COO-, or a single bond, and

n is 1 or 2.

10. Liquid-crystalline medium according to one or more of claims 1 to 9, wherein the medium has a birefringence of 0.105 or higher.

11. The liquid-crystalline medium according to one or more of claims 1 to 10, wherein the medium comprises a polymerizable compound.

12. Liquid crystal display comprising a liquid crystal medium according to any one of claims 1 to 11.

13. The liquid crystal display of claim 11, wherein the display is a VA, IPS, FFS, PS-VA, PS-IPS or PS-FFS type display.

14. Use of a liquid-crystalline medium according to one or more of claims 1 to 11 in VA, IPS, FFS, PS-VA, PS-IPS or PS-FFS displays.

15. Energy-saving display for games, comprising a liquid-crystalline medium according to one or more of claims 1 to 11.

16. A method of preparing a liquid crystalline medium according to any one of claims 1 to 9, comprising the step of mixing one or more compounds of formula I with one or more compounds selected from formulae IIA, IIB, IIC and IID and optionally with a polymerisable compound or other liquid crystalline compound or additive.